Iii 12.8 Wlj2.5 1.0 ,~ - 1IlI_ :: I.iii :1 2.2 ~ IIi£ ­ ~ ,~ 11 2.0 1.1 1.1 "M...... ~ I 1.8 25 111111.25 111111.4 111111.6 111111. 111111.4 111111.6

MICROCOPY RESOLUTION TEST CHART MICROCOPY RESOLUTION TEST CHART NATIONAL BUR[AU OF S1ANDARDS·1963·A NATIONAL BUREAU or STANDARDS-1963-A R(,.r.r:rI)J:1' r _.1 _ ~ 'CE DO NOT LOAN S:3-J ,-J. .. '"." '-I 7~ ..:;' '..;..,""!

FIBER AND PAPERMAKING CHARACTERISTICS OF BAMBOO

~ .­ ..... '-'" $", ~ "I.,.~ :; ~!r:" ,:: 'J'eehnical 'Bulletin No. 1361 iIIl .... ~ ",. .. '';'' , 'o,l."';' .' ,.,..... " C.l';" .... .) Agricultural Research Service UNITED SlATES DEPARTMENT OF AGRICULTURE

....:;

• Acknowledgment

The fiber and chemical studies described in this bulletin were per­ formed by the Herty Foundation, Savannah, Ga., through research contracts with the U.S. Department of Agriculture under the provi­ sions of the Research and Marketing Act of 1946. This bulletin re­ ports the final results of these studies.

Washington, D.C. Issued August 1966 Contents

Paue Summary ______1 Introduction ______2 Bamboo species studied ______3 Gross physical characteristics ______3 Determination of fiber dimensions ______4 Maceration of specimen ______4 Preparation of slides ______5 Measurement of fiber ______5 Evaluation of fiber measurements ______5 Fiber dimension data ______6 Chemical properties of bamboo ______7 Preparation and evaluation of bamboo pulp____ 8 Exploratory techniques ______8 Raitt two-stage and kraft single-stage cook­ ingprocesses ______8 PHot plant processing ______10 Papermaking ______12 Bleaching ______12 Refining ______13 Machine operation ______13 Physical Properties ______------______13 Literature cited ______16 Appendix ______16 Preliminary experiments for macerating culms ______16 Exploratory pulping studies ______18 r

FIBER AND PAPERMAKING CHARACTERISTICS OF BAMBOO 1

FmER AND P APERMAKING

CHARACTERISTICS OF BAMBOO

By J. R. HAUN, formerly horticulturist, Crops Research Division; T. F. CLARK, chemical engineer, Northern Utilization and Development Division; and GEORGE A. WHITE, agronomist, Crops Research Division, Agrir.ultural Research Service SUMMARY

Chipped bamboo culms of Phyl­ paper products. The various cook­ lostachys meyeri and P. bambuso­ ingprocedures had no appreciable ides compare favorably in density effect on bamboo average fiber to hardwood and softwood logs length or fiber width. not debarked. Stacked whole Bamboo raw material and pulp culms are more bulky than logs were analyzed for ash, pentosan, because of the airspace in bamboo and lignin content. A suitable culms. method was developed for the de­ As a rule, bamboo fibers are termination of lignin because the about the same length as those of methods used on wood were not hardwoods but are shorter than entirely satisfactory for bamboo. those of most coniferous woods. The chemical composition of bam­ Length-to-width ratios are higher boo culms is not widely different than those of wood fibers. The from that of other material used fibers of the tropical bamboo, in paper making. However, con­ Bambusa vulgaris, are longer siderable chemical variation was than those of other bam boo evident among the species of bam­ species. It was the only bamboo boo. Pulping procedures affected studied whose fiber approximated the chemical composition of bam­ the length of .southern pine fiber. boo about the same way they High length-to-width ratios in­ affect other papermaking ma­ dicate that bamboo fibers are terials. flexible and strong rather than Of the several pulping methods stiff and brittle. Slender, pliable used, the most promising were fibers are better for most paper the kraft single-stage and the because they give softness and Raitt two-stage processes. For smoothness rather than hardness pulp of the same yield, the latter and coarseness to the product. process gave better delignifica­ These characteristics i n d i cat e tion, there10re better bleachabil­ that bamboo may have a possible ity, with less removal of strength­ use in the manufacture of high­ giving pentosans than did the quality material for facial tissue kraft process. The net consump­ and for book, bond, and stationery tion of chemicals was less in the 2 TECHNICAL BULLETIN 1361, U. S. DEPT. OF AGRICULTURE

Raitt process than in the kraft Bamboo pulps are especially process. For equivalent yield and suH:ed to papers that require soft­ brightness, the chlorine required ness and absorptivity. The quali­ to bleach pulp cooked by the Raitt ties of bamboo pulp that favor its process was less than that re­ use fer these types of papers are quired to bleach pulp cooked by attributed in part to the slender­ the kraft process. Bleachable ness and pliability of the fibers. bamboo pulp made by either Bamboo appears to be suitable for method did not need refining be­ the following products: fore it was screened. Bamboo can a. Unbleached p u 1 p for the be pulped readily with less power manufacture of cable insulation and chemicals than wood. and fruit wrapper; pattern, in­ Considering the unbleached pulp dustrial saturating, and toweling yields, bleaching by use of Btand­ papers; and very light dry-formed al'd procedures produced satisfac­ board. tory brightness without undue b. Bleached pulp for the manu­ loss of yield or strength. The facture of absorbent molding, bleaching of bamboo pulp con­ Bible, bread wrapper (waxed), sumes less chlorine as a rule than and cigarette papers; cellulosic the bleaching of wood pulp. fiber media; sanitary papers r~_ Any of the bamboo species quiring softness; and blends for studied could be used for paper­ high-quality writing and airmail making because there were only stationery. minor pUlping diffel'ences among Other research on bamboo has them. The choice of species to shown the apparent suitability of grow, therefore, depends largely Phyllostachys ba1nbusoides for on agronomic characteristics and dissolving pulp (8)1 and struc­ a v ail ability of propagating ma­ tural board (6). This species may terial. Of the tropical bamboos, also be suitable for making news­ Ba1nbusa vulgaris had somewhat print-type papers, but this possi­ superior papermaking character­ bility requires additional investi­ istics. gation (7).

INTRODUCTION

Bamboo has been grown in the were carried out by the Herty United States on a limited basis Foundation to determine the suit­ for more than 50 years. It has ability of domestic bamboo for been utilized mainly for ornamen­ paper pulp. The first study by the tal purposes and to a limited ex­ Herty Foundation was started in tent for fishing poles. The Chinese 1953 to determine the compara­ have used it for centuries as a tive fiber dimensions and pUlping papermaking material, and in characteristics ·of 21 species of India it is one of the main raw bamboo. The second study, start­ materials used in the manufac­ ed in 1954, was designed to obtain additional comprehensive data on ture of paper. the pulping, bleaching, and paper­ Because of bamboo's potential­ ity as a new crop for the United 1 Italic numbers in parentheses refer States, fiber and chemical studies to Literature Cited, p. 16. FIBER AND PAPERMAKING CHARACTERISTICS OF BAMBOO 3 making characteristics of six boo were also studied. Prelimi­ species of bamboo selected from nary reports on some phases of among those studied in 1953. The this work have been published gross physical properties of bam- (12,18, H).

BAMBOO SPECIES STUDIED

Since 19J 9 the U.S. Depalt­ P. fiexuosa A. & C. Riv.__ 52686 ment of Agriculture has intro­ P. meyeri McClure 1. _____116768 duced and grown bamboo at its P. nidularia Munro _____ 63696 Plant Introduction Station, Sa­ P. nigra 'Hen<;n' (Lodd.) vannah, Ga. This station has one Munro 1. ______24761 of the most extensive collections P. pubescens Mazel ex. II. of hardy bamboos in the world. de Leh. ______80034 Many species have been widely P. purpumta 'Solidstem' distributed by the station to vari­ McClure ______77006 ous parts of the United States and P. pU7'pumta 'Straight­ are now available in the nursery stem' McClure ______77001 P. robromarginata trade. McClure ______67398 The e0/jnomically important P. 1Jiridis (Young) species of bamboo include both McClure1. ______77257 the tropiual (generally clump types) ancl the tempel'ate (gen­ P. vivax McClure 1 ______82047 erlly running types) species. The Tropical species from Maya­ U.S. Department of A!,'Ticulture's guez, P.R., and Plant Introduction collection in Savannah consists No.: Bmnbusa longispiculata mainly of temperate species. Ma­ Gamble ______178809 terial for the study of several tropical species was obtained B. tulda Roxb. ______21002 from the Federal Experiment B. tuldoides Munro _____ 80875 Station at Mayaguez, P. R., in B. vulg(L7'is Schrad. ______Guadua nngustifolia order that the pulping charac­ ]{unth ______132895 teristics of the tropical bamboos could be compared with those of the temperate bamboos. The tabu­ 1. Studied by the Herty Foundation in lation that follows shows the spe­ 1954. cies of bamboo studied by the Heriy Foundation in 1953-54. Temperate species from Savan­ Gross Physical nah, Ga., and Plant Introduction Characteristics No.: Phyllostachys arcana The diameter, volume, and McClure ______77007 density of samples of three bam­ P. aurea A. & C.Riv.____ 75153 boo species and for hardwoods P. aU'reosulc(~ta McClure_ 55713 and softwoods are shown in table P. bambusoides Sieb. 1. According to the table, Phylr & Zucc! ______40842 losiachys meyeri has smaller P. congesta Rendle ______80149 culms than P. bnmbusoides. How­ P. dulcis McClure 1 ______73452 ever, the culms of any bamboo are 4 TECHNICAL BULLETIN 1361, U. S. DEPT. OF AGRICULTURE vari"ble, depending on the age of three species of bamboo also stud­ plant, and on soil, climate, and ied by the Herty Foundation in other factors. Consequently, culm 1954 were­ sizes shown in table 1 are not Culm Culm necessarily representative for a height, -dia1nJ!t-fJ'T, particular species. The approxi­ feet inches P. meyeri ~.______33 1% mate maximum sizes of culms P. nigra 'Henon! _ 50 3 measured Ly McClure (5) for P. bambusoides ___ 75 5%

TABLE I.-Volume and drnsity of bamboo culms and of softwood and hardwood logs 1 -- - r Units Oven-dry weigbt Piled volume Species of a cord Number Average occupied by DenBityof Kind per cord diameter culms or logs Bulk density ------""lid portion lnchu Cubic!..1 Pound.!ct>rd Pounds/cubic foal PI,vUo.lach1l8 ,,,.yeri______Culm. 3,988 0.97 100 1,772 , 40.9 p,. niura ·.Hf.. nOfl~ ______._.. Culm. 2,223 1.30 83 1,143 34.0 P. bombu3"id""______••__ • , 34.8 Softwood (pinel.______CUllllB 8HO 2.02 79 1.200 Logs 45-100 7-10 '83 '1,575-2, 575 1 19-al Hardwood••_.______• __ Log. 45-100 7-10 '83 '1.745-3 .405 21-(,1

1 Datu Cor bamboo culmB obtained from Stevena (13) and !o~ loga, from Forest Prod:u.:tII Laboratory Technicnl Note No. 191 (15). : Value determined by displacement using ~hipped culm•. I Based on an nverng

Bamboo culms have been as­ Maceration 01 Specimen sumed to require considerably more space than pine logs on a Maceration proced ure consisted weight basis and thus would be of cooking internodal strips of impractical to handle and store. about 2 mm. by 2 mm. by 25 mm. Data in table 1 indicate that for 20 minutes at 15 p.s.i. steam whole culms may be more bulky pressure with a 10-percent N aOH than pine logs, but that chipped solution (Le., 100 grams per culms compare more favorably on liter); soaking 3 days in distilled a density basis. water with three changes of wa­ ter; and then dispersing for 45 seconds in an Osterizer.2 Later the Osterizer was replaced bya Determination of Hamilton-Beach Blendor. A 15- Fiber Dimensions second period with the blend~r running at low speed was found Preliminary experiments were best for dispersal. performed to determine an ap­ 2 Trade names are used in this pub­ ... propriate method for macerating lication solely to provide specific in­ culms that would minimize dam­ formation. Mentiol1 of a trade name age to the fibers. These experi­ does not constitute ~ ~uarantee or war­ ranty and does not signify that the ments are described in the ap­ product is approved to the exc1usion of pendix. other comparable prodUcts. FmER AND PAPERMAKING CHARACTERISTICS OF BAMBOO 5

Nieschlag et al. (9) determined made it. possible to deposit ap­ bamboo fiber dimensions by modi­ proximately 25 fibers on each fying the maceration techniques slide. The slides were placed on of Spearin and Isenberg (11) and a Temco hot plate adjusted to 50° of Jarman and Pickering (4). C., and the water was evaporated This modification involved boiling slowly. samples for 1 hour in I-percent NaOH; draining, washL2g with Measurement of Fiber hot 5-percent acetic acid, and then Slides with fiber suspensions digesting the material in an acidic were placed on the stage of an (acotic ac5d) solution of sodium ACM Projeh.-tina that enlarged chlorite until cellular bundles the image 10 times and projected were fairly well separated. Mac­ it on a ground-glass screen. Fi­ eration was usually completed in bers in the suspension were 6 to 8 hours. aligned parallel with the major axis of the slide by use of a micro­ Preparation of Slidea scope needle, taking care to Ten-gram samples of the mac­ straighten each fiber in order to erated raw material were dis­ f a c iIi tat e measurement. The persed in distilled water in a 500­ length of each fiber was then de­ ml. Erlenmeyer flask. By pro­ termined to the nearest 0.1 of a gressive decantation and dilution millimeter by use of the calibrated with distilled water, the fiber dis­ grid on the Projektina. persions were reduced to a con­ The slides were then trans­ sistency that weighed about 0.1 ferred to the mechanical stage of gram per liter. The actual fiber a binocular microscope where fi­ concentration was varied some­ ber widths were measured by use what according to average fiber of a 43-power objective lens, a length. 10-power ocular lens, and a Four test tubes 6 inches long micrometer scale. The resulting and 0.75 of an inch in diameter 430-power magnification made were filled with the fiber suspen­ possible the measurement of fiber sion, taking care to shake the widths to the nearest 0.001 of a Erlenmeyer flask vigorously be­ millimeter. A minimum of 200 fore filling each test tube. Next, measurements was made for each three drops of a I-percent solu­ average dimension reported. tion of Congo Red, or of Methy­ lene Blue, were added to the con­ Evaluation oj' Fiber Measurements .. tents in each of the test tubes and Fiber measurements (for each let stand 1 hour. Methylene Blue a v era g e dimension reported) was best for use on bleached were evaluated by the following fibers. procedure: After standing 1 hour, each 1. The total range of fiber lengths tube was shaken well and a little was divided into intervals of 0.1 of the fiber suspension removed of a mil1imeter. The number of with a 5 mm.-diameter pipette. A fibers in each length-interval was drop of fiber suspension was recorded, and the percentage of placed on one end of each of two fibers a in the interval was calcu­ slides. Eight slides were prepared lated. from fiber suspensions in the four 2. The mean length b of the fibers test tubes. Careful manipulation in each interval was calculated. 6 TECHNICAL BULLETIN 1361, U. S. DEPT. OF AGRICULTURE

The mean fiber length Of of the en­ quencya X length b X width c) tire lot was determined by multi­ by the mean weighted fiber area plying the interval a vel' age ~ (abe») lengths by the interval percent­ ( 100 . Thus, the frequency ages, adding the interval prod­ uct-c. and dividing the sum by distribution by weight 100, as follows: Mean fiber length abc ~ (ab) ----X 100. b'=---­ ~ (abc) 100 3. The mean fiber width c' was ob­ Fiber Dimension Data tained by substituting the inter­ In most cases, measurements of val mean fiber width c in the pre­ fiber length and fiber width were ceding formula, thus: Mean fiber made on raw material obtained ~ (ae) from several places on each culm. width c' = ---­ Fiber lengths and widths of the 100 lower one-third (base) and the 4. The mean weighted fiber area upper two-thirds of the culms was calculated from the sum of were averaged (table 2). The the products of the lengths X length-to-width ratios are means widths X percentages of fre­ of ratios of the upper and lower quency, as follows: Mean weight­ portions of culms and, therefore, ~ (abc) differ slightly from ratios that ed fiber area = ---­ 'would be obtained by using aver­ 100 age length and width means 5. Finally the frequency distribu­ shown in table 2. Analyses of tion of fibers by weight per length variance were performed and interval W.ftS c~.lculated by divid­ Duncan's MUltiple Range test ap­ ing the interval fiber area (fre­ plied to each set of data.

TABLE 2.-Mean fiber dimensions of bamboo raw material

:Mean fiber Mean fiber Length-to­ length J I width J Speci"" width ratio J

•\lm. ,I[m. BamblU_~_"' _ ____ .. __.... ____ ...... _____ .. ______'" 1.38 be .0102 abed 134 e[ P. ball~btUOide8 __ ..___ • __ ...... _____ ...____ • 1.37 be .0104 abed 132 e! P. pubescens.....__ ._•• • __ ...... _____.._ 1.30 hc .0093 cde 140 de! P. af.trea8uicaia ..... ___ .. "' ..... ______.. ___ .. ______1.26 be .0082 e 156 bede! P. dulciJJ ...., ___ •••_•••_. ___ .. _..__ ...... __ _ 1.20 e .0096 bcde 124 r

1 For a given measurement. two means followed by the same letter or letters are not significantly different at the 5-DerCp.nt level .according to Duncan's Multiple Range test. The same degree of significance applies to ratios of length-to·width. FmER AND PAPERMAKING CHARACTERISTICS OF BAMBOO 7

Chemical Properties Bamboo fiberized raw material of Bamboo was analyzed for ash, lignin, and pentosan by TAPPI3 standard Bamboo for analyais was cut methods, as follows: from whole culms by use of a a. Ash con ten t, by use of power saw and identified as to po­ TAPPI method T 15 m-48. sition on the culm and number of b. Lignin content, by use of nodes per section. Samples were TAPPI method T 13 m-45. The then split lengthwise with an ax time o~ digestion in 72-percent into pieces about % of an inch H SO. was extended to 20 hours. wide and 6 inches long and then 2 fiberized in the 015 Jackson & c. Pentosan content, by use of Church refiner mill. TAPPI method T 18 m-20. Krob­ rfhe fiberized raw material was er's table (2) was used for con­ taken from the refiner mill and verting weights of furfural gluco­ further reduced in size in an Abbe side to pentosan. mill that had %6-inch perfora­ The results of analyses of vari­ tions. It was then screened on a ance for duplicate determinations set of Syntron sieves to obtain of ash, pentosan, and lignin in material that passed through a samples of bamboo raw material 50-mesh sieve but was retained from the lower one-third of culms on a 100-mesh sieve. are given in table 3.

TABLE 3.-Composition of bamboo raw material from lower one-third of culms

Species Ash l Pentosnn' Lignin'

BumbuBa tuldu______-______6.2Percent a Percent Percent g Ph1/lloslachUB bamblUlOidu ___ -.______2_1 b 18.5 e 19.7 P. Pirar______1.8 be 22.3 a 32.2 b 22.3 a 24.6 0 P. purpurutu ·Solidslem·_...______1.8 be 21.6 ab 26.9 d P. uureogUkula______1.8 be B.luldaides______.______1.( cd 20.6 bcd 21.2 Ig P. ftexuaHa __ .______1.4 ed 19.4 de 19.6 g 20.1 cd 24.4 e 21.0 nbc 23.0 el ~: ri:tiii_'::::::::::::::::::::::::::::::::::::: U ~~ 18.4 e 21.6 Ig 22.2 a 36.8 a ~: ~;;~t:IH:~~~!~::::::::::::::::::::::::::::::: U ~: 18.2 e 29.3 c Pine chips .• ____ . _.. ______.._. •. ..:;._:.:;__:.=_.:..:__ ...:.:.8:...... --=e_-'--.::..:..:.:....._-'--'-.::.:...:.:.....--=:...... _ 14.4 I 27.0 d

1 For a given metulurement. two means followed by the srune Idler or letters are not s!snificantly different at the 5-11ercent level lIccording to Dunclln's Muitillie Range test.

In contrast to the procedure de­ cent, and boiling for 1 hour. The scribed in the foregoing para­ residue is then recovered and graphs, a fairly simple and rapid weighed with correction for ash method for the determination of content determined by ignition of lignin has beel'l developed by the the dried residue. Agricultural Hesearch Service's Northern Utilization Research 3 Technical Association of the Pulp and Development Division. '.chis and Paper Industry. Also the name of method, which 15 a moc1ific~ttion of the official pUblication of this Associa­ the procedure dt'scribed by Aro­ tion. All publications of the Technical novsky et al. (1), involves 2 hours Association of the Pulp and Paper In­ dustry may be obtained from the offices digestion in 80-percent sulfuric at 360 Lexington Avenue, New York, acid at 5° C., dilution to 3 per­ N. Y. 10017. 8 TECHNICAL BULLETIN 1361, U. S. DEPT. OF AGRICULTURE PREPARATION AND EVALUATION OF BAMBOO PULP

Exploratory Techniques tory Techniques." In these stud­ ies, the material was cooked in a Studies were conducted with 5-gallon or larger digester, and small amounts of raw material to the results allowed an adequate determine the chemical-to-bamboo evaluation of the pulp. ratio required to neutralize or­ ganic acids and solubilize the ce­ Bamboo for these two processes menting sub s tan c e (lignin) was prepared from basal sections enough to separate fibers for the (lower one-third) of culms by determination of pulp yields. For chipping in a Carthage 4-knife this purpose, small digesters hav­ chipper. This machine made good ing a capacity of 900 ml. were chips, but it also made a lot of made from 8-inch lengths of 3­ splinters. Splinters were sepa­ inch pipe closed at one end by a rated by hand and chopped into welded plate and at the other end suitable size with a hatchet. by a threaded cap having a ther­ Treatments given the bamboo mometer well. The digesters were chips and splinters follow. heated in an oil bath over a gas 1. Raitt two-stage cooking flame. (10): Using 20 grams per liter Bamboo for these digesters was active a 1k a I i (calculated as prepared by cutting culms into NaOH) at a liquor volume of 8 sections with a power saw and to 1, bamboo was cooked for 1 splitting the sections into splint­ hour at 100 0 to 110 0 C., followed ers. Both nodal and internodal by cooking 1 hour at 150 0 C. Then sections were included. Splinter using the same liquor volume con­ dimensions ranged from 1 to 10 taining 50 grams per liter active mm. tangential, 1 to 6 mm. radial, alkali (calculated as NaOH) , the and 74 to 202 mm. longitudinal. material was cooked 2 hours at Mean dimensions were 5 by 3 by 130 0 to 140 0 C. 150 mm., respectively. Splinters 2. Kraft single-stage cooking: from each culm section were dis­ Using 15-percent active N3.:!O tributed equally among digesters. (calculated on moisture-free bam­ The exploratory pulping studies boo) and an 8 to 1 liquor volume, and their results are described in bamboo was cooked 2 hours at the appendix. 160 0 to 170 0 C. Fiber dimensions of the pulp Raitt Two-Stage and Kraft prepared by the kraft process Single-Stage Cooking were determined according to the techniques described in the sec­ Processes tion "Determination of Fiber Comparative cooking studies Dimensions." Results of these using the Raitt and kraft proc­ determinations are shown in table esses were conducted with con­ 4. stant chemical-to-bamboo ratios Kraft-cooked pulps were pre­ on larger samples of material pared for chemical analysis by from various spedes of bamboo oven drying followed by pulveriz­ than described under "Explora­ ing in an Abbe mill. The content FmER AND PAPERMAKlNG CHARACTERISTICS OF BAMBOO 9 of ash, lignin, and pentosans is od T 22 m-50. Digestion time was shown in table 5. Methods used extended to 20 hours. for the various constit .:ent anal­ c. Pentosan content, TAPPI yses were: method T 19 m-20. Krober's table a. Ash content, TAPPI method (2) was used for converting T 211 m-44. weights of furfural glucoside to b. Lignin content, TAPPI meth­ pentosan.

TABLE 4.-Fiber dimensions of bamboo pulp prepared from the basal sections of culms in 5-gallon digesters by the kraft process

Fiber dlmensions I Specles pulped Length Width

Mm. Mm. Bam"""a ""Igaria ______2.09 a 0.0109 ab 192 lib 1.80 ab .0088 de 204 a 1.7& be .0108 ab 160 defgh lPhlll!o.ta~hY8 ~~~~:a_~======:=:===:=:=:::=::=: ru~romarginala ______1.66 be .0091 cde 182 be 1.65 be .0090 cde 184 be ~: f~rd:id~~~~~:======::::::=::=:=:::======::: 1.64 be .0097 abede 170 eder P. f/e;rtw8a ______1.63 be .0094 bcde 174 bcd Guadua anguli/olia ______1.62 be .0112 a 144 hi P. purpura/a 'Straightstem'______1.54 bed .0087 de 177 bed 1.50 bcd .0098 abcde 153 efghl ~: ~r:::::~-~=:==:==:::=:::==::::::::::::==: 1.48 bed .0104 abc 142 hi PP... aureanidularia______1.44 cd .0088 de 165 cdefg P. congula______1.44 cd .0085 e 169 cder P. rrirCl% ______1.43 cd .0084 e 170 cder 1.43 cd .0101 abcd 140 1 P. aur.",ulcala______1.23 d .0084 e 146 ghl

, For a given measurement, two means followed by the same letter or lettera are not significantly dlfferent at the 5-percent level according to Duncan's Multiple Range test.

TABLE 5.-Composition of bamboo pulp prepared from the basal sections of culms in 5-gallon digesters by the kraft process [Results are duplicate determinations]

Spccies pulped Ash I Pentosan I Lignin I

Percent Percent Percen' BambiUla "'Igaria______2.85 a 20.1 b 7.6 d Phllllo.lru:hIl8 """gula______2.25 ab 26.6 a 9.7 c P. aurea______...... ____ .... 1.85 ab 14.9 c 6.6 d 1.50 ab 9.0 d 21.3 a P.~I~;';~~~:==:::::::=:=::::=::=::==:::=::=::::= bambuoidea ______1.25 ab 20.7 b 5.0 e P. ri.Cl%______1.15 Ilb 20.5 b 17.3 b 0.90 b 19.8 b 18.0 b

'For a given measurement, two nleans followed by the same letter or letters are not significantly different at the 5-percent level according to Duncan's Multiple Range test.

Representative data for some pulps. Refining by beating was properties of the pulps produced performed in a llh-po\1nd Valley by the Raitt two-stage and the beater, and pulp was sampled at kraft single-stage processes are intervals to determine freeness shown in table 6. TAPPI method and sheet making. A Rice-Barton T 200 m-45 was used to evaluate Dynapulper was used in lieu of the strength and other physical the British disintegrator for characteristics of the bam boo clearing the pulps before sheet 10 TECHNICAL BULLETIN 1361, U. S. DEPT. OF AGRICULTURE making. Based on a test from one tion, these departures were justi­ cook, the dynapulper appeared to fied. Freeness was determined by have no appreciable effect on the use of TAPPI method T 227 m-50. freeness of the stock. The beater Handsheet forming was done bedplate clearance chamber did by use of Noble and Wood equip­ not have water inlets, but by ex­ ment and procedure, except that ercising care, it was possible to sheets were dried on an electric keep the pockets free of accumu­ hot plate instead of on a drum lated fiber. Instead of the stand­ dryer. Six handsheets were made ard 5,500 grams on the bedplate for each freeness determination. lever arm, a total of 6,440 grams One of these sheets was preserved was used. Because the experi­ for reference; the other sheets mental results were subjected were measured, tested, and the only to comparative interpreta­ results averaged.

TABLE 6.-Some physical prope'rties of bamboo pulps prepared by Raitt two-stage and kraft single-stage processes and refined to J,.OO ml. Canadian Standard' (C.S.) freeness

Pulp Beating Burst Tear Pulping method and species tested yield time factor factor

Percent Minulea G./8Q. cm./u./8Q. m. G./U./8Q. m. Raitt tW

First-sInge conditions Second-sInge conditions Totul alka­ linity Active Na,O Active Na,O of both stages Perman- Bright- Type of cook and number; Liquld- Liquid- (nctive Pulp gannte Chlorine ncss bamboo species puiped I On Time to- On Time Sulfidily to- Na,O yield number blench 1'hoto­ Con- busis of on tern- solids Con- basis of on tem- of solids on basis voila i centra- mois- pemture ratio centra- mois- perature liquor ratio of mois­ lion ture-free tlon ture-free lure-free bamboo) ---bamboo ------bamboo ------~ G./I. Percent lIoar. G./I. Percent Hour. Percent Percent Percent Percenl Percent R 1; PhylloBtachys viridiB ______15.6 5.6 2.0 8.59 48.4 37.0 8.0 0 8.53 42.6 34 9 8.2 73 ~ R 2; P. bambl/soides______15.6 6.5 1.0 4.16 51.9 84.5 0.5 0 6.66 41.0 37 19 13.9 84 R 8; P. bambusoicJes ______18.7 7.8 1.0 4.16 51.9 21.6 0.5 0 4.17 29.4 36 21 14.5 - ~ R 4; P. bambu8oicJes ______11.8 4.4 1.0 3.78 86.8 14.0 8.0 34 8.30 18.4 42 21 9.0 - i?: R 5; P. bambusoides______13.2 4.2 1.0 8.18 87.7 18.8 8.0 84 3.67 18.0 41 23 10.7 - R 6; P. bambl/soides______14.6 4.5 2.0 8.08 40.8 12.8 2.0 34 3.14 17.3 44 19 - ­ > R 7; P. bambuBoides ______11.5 4.2 1.0 3.65 87.0 13.7 2.0 23 3.7l 17.9 43 - 10.9 - El R 8; P. vivax______13.6 6.8 2.0 5.00 37.6 14.2 8.0 19 3.73 21.0 87 23 7.0 ­ R 9; 70 percent P. bambl/8oides 13.6 4.0 2.0 2.94 38.8 14.8 2.0 11 4.38 18.8 46 18 9.9 75 ~ and 80 percent P. nigra 'Henon'. RIO; 70 percent P. bambltBoides 11.9 5.1 1.0 4.29 40.0 16.4 2.0 4 4.10 21.5 48 25 9.2 - a and 30 percent P. nigra. ~ R 11; 70 percent P. bambuBoides 14.6 5.8 1.25 8.98 85.1 14.0 1.75 0 4.00 19.8 42 17 9.2 69 and 80 percent P. meyeri. R 12; .70 percent P. bambuBoides 14.6 5.8 1.25 8.98 85.1 14.0 1.75 0 4.00 19.8 41 15 9.2 69 ~ and 30 percent P. meyeri. R 13; 67 percent P. bambll80ides 12.4 5.9 1.0 4.76 82.2 15.8 2.0 0 4.75 21.2 46 - 11.1 ­ and 83 percent P. llivax. 49 13.8 64 R 14; 70 percent P. bambll80ides 15.1 5.8 1.0 8.84 86.8 14.0 2.0 0 8.86 19.8 - ~ and 30 percent P. vivax. Ul R 15; P. bambu8oides ______15.0 6.7 1.25 4.44 37.4 16.7 2.25 0 4.47 23.4 49 - 5.2 - R 16; P. bambusoieles ______14.7 7.0 1.25 4.76 36.7 17.6 2.25 0 4.80 24.6 42 - 10.0 77 ~ K 17; P. bambuBOides ______40.5 18.1 3.00 4.47 - - - 0 - 18.1 41 - 6.0 - o R 18; P. bambllsoides______15.3 7.0 1.25 4.58 84.1 15.7 2.25 0 4.60 22.7 42 - 10.0 77 Ul R 19; P. ba7l1buBOidC8______18.7 6.2 1.25 4.58 86.2 15.9 2.25 0 4.89 22.1 5t - 12.2 - K 20; P. bambusoide.<______42.0 19.2 8.0 4.57 - - - 0 - 19.2 40 - 9.6 '~9 ~ R 21; P. bambu"oide.L ______14.7 6.1 1.25 4.15 38.9 15.1 2.25 0 3.88 21.2 87 - 7.4 -­ R 22; P. bambusoides______14.7 6.0 1.25 4.08 88.8 15.1 2.25 25 3.89 21.1 43 - 4.6 7t! bj R 23; P. bambusoides______15.5 6.4 1.25 4.18 89.5 15.4 2.25 25 3.90 21.8 36 18 9.5 75 > R 24; P. b,"nbusoirfes______15.0 6.3 1.25 4.20 38.9 15.1 2.25 25 3.88 21.4 43 16 11.7 65 R 25; P. bambusoides ______15.4 6.1 1.0 8.96 88.4 15.1 1.5 21 3.93 21.2 41 20 7.8 66 ~ R 26; P. bambusoides______15.4 6.1 1.0 8.96 38.4 15.1 2.0 21 3.93 21.2 43 20 7.8 70 o K 27; P. bambu8oides______40.0 18.0 2.0 4.50 - - - 23 - 18.0 45 27 8.2 57 o R 28; P. bambll8oides ______14.3 9.1 1.0 6.36 35.4 15.7 2.5 22 4.43 24.8 40 22 9.4 67 K 27; P. bambu8oides______32.2 18.1 3.0 5.62 - - - 29 - 18.1 40 19 8.3 69 K llO; P. dulcis______82.8 18.1 2.5 5.52 - - - 30 ­ 18.1 43 15 77.1 66 1 The types of cook Rand K refer to the Raitt two-stage and the kraft slngle-stage treatments, respectively. Numerals that follow these letters are for ..... "-'

PA1'ERMAKING

The experimental bamboo pulps Hooker rubber-lined chlorinator made in the pilot-plant digester that had a diameter of2 feet and were used singly or in combina­ a height of 14 feet and was tion with conventional pulps to equipped with a rubber-lined side prepare furnishes for a variety of tube 8 inches in diameter. paper and pulp products. Conven­ Circulation of pulp in the tional pulps used in the furnishes chlorinator and side tube was ac­ were commercial southern pine complished with a centrifugal bleached kraft, commercial hard­ wood bleached soda, an oalr pump having a 4-inch inlet (suc­ groundwood, a flax pulp, and a tion) and 3-inch vertical dis­ rag pulp. Additives, fillers, dyes, charge. The pump was driven pigmen t s, and sizing agents 1,750 r.p.m. by a direct-connected (starch, clay, and alum rosin) 10 hp. motor. The permanganate were also included in the fur­ number (TAPPI method T 214 m­ nishes according to the charac­ 50) was used to calculate the teristics needed in the final prod­ amount of chlorine required. uct. Chlorine was injected from a cylinder mounted on a platform scale directly into the stream of Bleaching slush pulp as it was pumped Bleaching was accomplished by through the rubber-lined side use of a three-stage procedure tube..After 30 minutes, an NaOH ) that involved chlorination, caustic solution was added at the top of extraction, and hypochlorite oxi­ the chlorinator to neutralize the dation. A 75-pound Niagara-type acids that had formed and to ad­ tile-lined Valley beater was used just the pH to the range of 10 to to prepare slush stock of 3-percent 11. Circulation was continued consistency from the pulps de­ another 5 minutes. The stock was scribed in table 7. Chlorination then pumped out to a 300-pound was performed in a 150-pound hollander-type tile-lined Valley FIBER AND PAPERMAKING CHARACTERISTICS OF BAMBOO 13 beater equipped with an octagonal or other forms of pulp; to mix the drum washer. ingredients or "furnish"; and to Caustic extraction was accom­ waterlog, or "hydrate", the fibers. plished by adding NaOH to the Refining of pulp was accomplished pulp in the beater and then heat­ with either a Valley pony jordan ing the pulp with direct steam. or a Hermann claflin. The amount of 'Nl,~OH added was The prepared stock was pumped equal to 5 percent uf the weight of into agitated stock chests, then oven-dry pulp. After heating for through a Valley 6-plate dia­ 1 .hour at 50° C., the pulp was phragm screen to remove shives washed. and coarse dirt, and finally through a Bird Dirtec centrifugal In the final stage, a calcium cleaner to remove fine dirt before hypochlorite (HTH) solution was being pumped into the regulating added, and the pH of the stock ad­ feedbox of the paper machine. j ush~d to a range of 9 to 10 by adding N aOH. The stock was cir­ culated in the beater with hy­ Machine Operation pochlorite for 1 hour, after which Sheet forming and drying were the pulp was washed. If a hand­ carried out by using a Pusey­ sheet of the pulp lacked the re­ Jones fourdrinier with 31-inch quired brightness, at least one wire and 28-inch trim. This ma­ more hypochlorite stage was chine was complete with shake, carried out. Pulp was stabilized three 6-inch flat boxes, a 12-inch­ by the use of sulfurous acid diameter brass couch roll, and a formed in situ by injecting S02 jacketed top roll; rubber bottom from a cylinder of the liquefied and granite top first press; rubber gas. The final bleached pulp was bottom and stonite top reversed pumped from the beater to a stock second press; Mount Hope ex­ chest, run over the fourdrinier, pander roll; nine 24-inch-diameter and taken off as roll pulp or "'wet dryers; 7 -roll calender; and a laps" after the second press. Pusey-Jones winder. Brightness of the pulp was de­ termined by a Photovolt instru­ Physical Properties ment, which measured the reflect­ ance in comparison with a stand­ Basis weight, caliper, burst fac­ ard white. Data on bleaching are tor, tear factor, breaking length, shown in table 7. folding endurance (Massachusetts Institute of Technology), poros­ Refining ity, and smoothness of machine papers were determined in ac­ In preparing the stock for the cOl·dance with TAPPI Standard paper machine runs, a 300-pound Methods. Composition of the vari­ hollander-type tile-lined Valley ous furnishes and properties of beater was used to break up laps the products as shown in table 8. 14 TECHNICAL BULLETIN 1361, U. S. DEPT. OF AGRICULTURE

TABLE 8.-Composition and physical characteristics of papers made on pilot fourdrinier

Type of cook. number, and Additives Type of percentage of bamboo pulp; Basis paper made perc'eIltage of other pulp I weight Size Alum Clay Starch Dye ------

Pd. Pel. Pel. Pet. G'/.q. m. Bond. ______R I, 88 percent; bleached 2 a 12 - Pafer blue and 81.4 kraIt. 17 percent.' . percent TiO,. Bond______R 2, 80 percent; bleached 1 2 10 5 Paper blue______78.9 kraft. 20 percent. Bond______• __ R 8, SO percent; bleached 1 2 10 4 Pllper blue______85.1 kraIt, 20 percent. Saturating_____ R 4. 90 percent; bleached - - - - - 166.S kraft. 10 percent. Tlssue______R 5, 90 percent; bleached --- -- 87.8 kraIt. 10 percent. Wet strenght___ R 6, 100percenL______2-percent ulormite and;3.6-percent alum; adjust 93.2 pH to 4.0.

Book.______• __ R 7, 66 percent; soda, 84 per. 1.5 3.0 25.0 - - 72.7 cent.' Magazine______R 8, 66 percent; bleached 1.5 2.0 26.0 - 8 percent TiO, 86.7 kraft, 12 percent and soda. and Brilliant 82 percent. blue.2R. Saturating..___ R 9 and RIO; no other pulp___ - - - -- 92.6 Saturating_____ R ll.and R 12; no other pulp__ - - -- - 214.8 Saturating____ R 18 and R 14; no other pulp__ - - - 155.2 Bond. _____ •__ R 16 and R IS; no other pulp__ -2 2 15 -4 Paper blue..____ 25S,1 Book______R 15 and R 20, 50 percent; 1.1 1.5 25.0 Paper blue__ •__ . S1.2 aoda 26 percent; and - Book.______bleached kraft. 25 percent. R 15 and R 21; no other pulp._ 1.0 2.0 80.0 - Paper blue______96.0 Bond____ • __ .. R 22, 50 percent; rag pulp. 50 2.0 2.0 15.0 4.0 - 66.2 percent. Tissue______R 23, 100 percent______-- - - - 88.2 Food container R 15, 100 percenL..______1.9 1.9 - - - 22.7 Bondboard. ______R 28 and R 24. 50 percent; 8 2 80 - 95.4 flax pulp. 60 percent. - Bible..______R 28 and R 24, 50 percent; 8 2 50 - 44.6 flax pulp, 50 percent. - CorruKUting K 27. 100 percent.______2 1 - - 12.4 medium. - Colored K 27.69 percent and K29. 31 2.5 8.1 - - Congo red..____ 45.5 wrapper. percent. Magazine..____ K 30. 22 percent and R 26, 46 - 10 2 1 percent TiO,__ 69.5 percent; oak groundwood , - 16 percent and soda, 16 per­ cent. Stationery_____ R 25, 63 percent and R 2S, 87 2 3 11 2 79.1 percent. - FIBER AND PAPERMAKING CHARACTERISTICS OF BAMBOO 15

TABLE S.-Composition and physical characteristics of papers made on pilot fourdrinier

Mallllllch usetts Breakinc Institute of Tear factor • strength Teehnology Porosity Smooth- Brightness Caliper Burst double fold ness Photo­ factor' section volta 8 ply MD- CD' MD' CD' MD' CD' WS' FS' ------G'/8q.em'/ Giu./ G./O./ MilB o./.q. m. sq. nt. sq. tn. M. 11

6.2 20.4 78.8 83.7 4,580 2,360 50 47 2.7 2.7 4S.4 ­

4.5 12.6 48.1 57.8 2,940 1,100 1 1 9.8 9.3 11S.4 76 5.6 18.8 50.8 58.8 3,690 1,850 4 2 36.4 8S.4 117.2 68

7.1 16.0 76.7 78.8 4,250 1,5RO 3 1 7.7 7.8 24.0 ­ 13.5 18.7 82.1 84.4 4,670 2.J50 35 11 11.2 11.2 37.6 ­ 9.8 21.3 79.2 83.7 5,280 2,750 13 9 1.S 21.S 26.8 - 4.9 11.2 24.8 27.9 1,700 720 1 5 154.9 155.0 104.8 74 4.4 19.9 72.S 72.6 8,690 1,720 5 8 24.5 27.7 168.4 70

4.0 19.0 47.9 47.9 4,510 2,150 10 8 410.7 410.8 286.8 ­ 3.6 27.6 10.4 11.3 6,340 2,620 69 58 80.3 80.2 8S.4 ­ 2.0 lS.S 41.0 42.0 3,840 1,920 1 1 92 92 184.4 - 14.8 18.0 86.2 92.4 4,570 2,730 66 49 11.5 11.5 64.0 ­ 4.9 16.2 67.0 75.5 4,S10 1,960 7 5 155 155 104.8 74 2.3 11.0 47.1 47.1 3,440 1,050 1 1 68.0 68.1 143.2 ­ 11.3 17.0 62.6 66.6 4,440 2,410 10 8 3.3 8.2 47.2 Not bleached. 8.1 15.5 77.1 81.5 4,700 1.620 1 1 2.9 2.9 74.0 Too red for read­ ing. 4.0 22.3 61.9 73.4 5,470 2,400 1 1 62.4 62.4 10S.8 68

8.9 28.1 S3.2 69.6 5,800 2,280 15 9 65.8 65.8 90.0 73

'Letter. Rand K refer to the Raltt two-stage and the kraft single-stage treatment, respectively. The first numeral following these letters can be used to identify the species of bamboo in the cook and the conditions under which the pulp was made by referring to table 7. Where the percentage oC bamboo pulp is not shown, the final composition of the pulp did not differ significantly ,from that shown in table 7. • Burst factor-unit oC measure is grams per square centimeter per grams per square meter. J Tear factor-unit of measure is grams per gram per square ,meter. ,4 MD means machine direction: OD, across machine direction. • WS meana wire .ide up;FS, felt side uP. • Bleached kraft means this type of pulp made from southern pine and commercially available. T Soda means this type of .bleached pulp made from hardwood and commercially available. 16 TECHNICAL BULLETIN 1361, U. S. DEPT. OF AGRICULTURE

LITERATURE CITED

(1) ARONOVSKY, S. 1., NELSON, G. H., (7): 472-475. and LATHROP, E. C. (8) MATUSZEWSKI, R. S., 1943. AGRICULTURAL RESIDUE CLARK, T. F., and WOLFF, I. A. PULP8--BLEACHING STUD­ 1960. DISSOLVING PULPS FROM IES ON STRAW PULPS. DOMESTIC TIMBER BAM­ Paper Trade Jour. 117- BOO-PHYLLOSTACHYS (25) : 38-48, illus. BAMBUSOIDES. TAPPI43­ (2) Association of Official Agricultur­ (6): 591-596. al Chemists. (9) NIESCHLAG, H. J., NELSON, G. H., 1950. OFFICIAL METHODS. Ed. WOLFF, I. A., and PERDUE, R. E. 7, 833-835. Washington, 1960. A SEARCH FOR NEW FIBER D.C. cRoPs.TAPPI 43(3): (3) Food and Agriculture Organiza­ 193-201, illus. tion. (10) RAITT, W. 1953. RAW MATERIALS .FOR 1925. BAMBOO AND GRASSES FOR MORE PAPER. Tech. Rpt. PAPER PULP. World's 6: 128. Rome, Italy. Paper Trade Rev. 84: (4) JARMAN, C. G., and PICKERING, 56~568, 618-620. G. B. (11) SPEARIN, W. E., and ISENBERG, 1954. AN IMPROVED METHOD I. H. FOR THE PREPARATION OF 1947. THE MACERATION OF ULTIMATE FIBRE. Colon. WOODY TISSUE WITH Plant and Animal Prod. ACETIC ACID AND SODIUM 4: 350-351. [Great CHLORITE. Science 105: Britain] 214. (5) MCCLURE, F. A. (12) SPROULL, R. C. 19.5'1. BAMBOO OF THE GENUS 1955. PRELIMINARY .INVESTIGA­ PHYLLOSTACHYS UNDER TIONS ON ALKALINE PULP­ CULTIVATION IN THE ING OF BAMBOO. TAPPI UNITED STATES. U.S. 38 (10): 593-596. Dept. Agr., Agr. Handb. (13) STEVENS, R. H. 114, 69 pp., illus. 1958. BAMBOO: THE FACTS AND (6) NAFFZIGER, T. R., CLARK. T. F., THE PROBLEM. Chemurg. and WOLFF, 1. A. Digest 17 (1): 8-12. 1961. STRUCTURAL BOARD FROM (14) DOMESTIC TIMBER BAMBOO 1958. BAMBOO OR WOOD? South­ -PHYLLOSTACHYS BAM­ ern Pulp and Paper Mfr. BUSOIDES. T APPI 44- 21(3): 93, 94, 130, illus. (2): 108-112. (15) U.S. Department of Agriculture. (7) CLAltK, T. F., and WOLFF, 1953. DENSITY, FIBER LENGTH, I. A. AND YIELDS OF PULP FOR 1961. NEWSPRINT FROM DOMES­ VARIOUS SPECIES OF WOOD. TIC TIMBER BAMBOO­ Forest Prod. Lab. Tech. PHYLLOSTACHYS BAM­ Note 191. Madison, Wis. BUSOIDES. TAPPI 44- (Revised.)

APPENDIX

Preliminary Experiments mechanically in a 015 Jaclmon & Church refiner. This method for Macerating Culms caused excessive breakage of The following methods were fibers. tried for preparing fiber macer­ 2. Culm pieces of similar size ates from bamboo culms: were boiled at atmospheric pl'es­ 1. Culms were cut into pieces ¥s sure in a 10-percent NaOH solu­ by 1/8 by 1 inch and macerated tion (TAPPI method T 10 m-47). FIBER AND PAPER1vIAKING CHARACTERISTICS OF BAMBOO 17

This treatment, designed for pulp d. in 2.0- and 2.5-percent and paper manufacture, was too NaOH solutions at 150 0 to 165 0 mild to macerate the culm mate­ C. for 1.5 hours. Strips cooked ria1. It did not affect the outer in this manner were softened layer of the pieces. more than they were when 3. Strips of culms were cut 3 to 9 cooked in the l.4-percent solu­ mm. tangentially, 1 to 6 mm. tion but still were not soft radially, and 135 to 165 mm. enough for damage-free separa­ longitudinally (average dimen­ tion of fibers. sions were about 5 by 2.5 by 150 4. About 5 grams of matchstick­ mm.). The strips were cooked size pieces of culm were boiled for under the following conditions in 20 minutes in water to expel air; small digesters (3 inches in diam­ immersed in a hypochlorite solu­ eter by 8 inches in length) im­ tion (Chlorox 1 :1) for 2 hours; mersed in an oil bath: washed in distilled water; im­ 0 0 a. In water at 150 to 165 C. mersed in a 3-percent Na2SO a 0 for 3 hours. In this tre~\tment, solution at 70 C. for 15 minutes: the strips were softened enough washed in distilled water ; im~ to pull apart with the fingers, mersed in Chlorox again for 2 hours; washed; immersed in a but the resultant slivers were 0 too raw for separation into in­ 3-percent Na2 SOa solution at 70 dividual fibers without damage C. for 15 minutes; washed in dis­ to the fibers. tilled water; placed in a 500-ml. Erlenmeyer flask with 125 ml. of b. Ip a 0.78-percent Na2 C03 solutIOn (approximatelyequiva­ distilled water, shaken vigorously, lent to 4.45-percent Na..O) at decanted, and diluted until there 150 0 to 165 0 C. for 2 -hours. were only about 25 fibers in one This treatment did not soften drop. This treatment produced the strips. The carbonate may bleached fibers that would not have suppressed hydrolysis of stain readily, but they were too carbohydrates (hemicelluloses) fragile for reliable measurement. that \\'ould normallv have oc­ 5. About 5 grams of matchstick­ CUlTed by unbuffered organic size pieces of culm were boiled in acids present or formed in the water 30 minutes to expel air; woody material. Hydrolysis boiled 30 minutes in a 10-percent could have caused fiber embrit­ NaOH solution; washed; placed in tlement and some fiber break­ a 500-ml. Erlenmeyer flask with age. This would alter dimen­ 125 m!. of distilled water, shaken sions of fiber fragments but not vigorously, decanted, and diluted ... of compJete fibers. Some swell­ until there were only about 25 ing mig-ht occur under alkaline fibers in one drop. This method conditions. gave incomplete separation of the c. In a l.4-percent NaOH solu­ outer wall (0.5 mm. thick), tion (approximately equivalent although the inner wall was fairly to 1.0-percent Na~O) at 150 0 well macerated. The method was to 165 0 C. for 1.5 hours. This repeated extending the period of treatment softened the strips boiling in water to 4 hours, but more than when they were there was no improvement in re­ boiled in water alone for 3 sults. hours, yet not enough to permit 6. About 5 grams of matchstick­ separation ·of the fibers without size pieces of culm were boiled in damage to them. water 30 minutes to expel air; 18 TECHNICAL BULLETIN 1361, U. S. DEPT. OF AGRICULTURE

heated to 70° C. in a 4-percent water, and then dispersed in the HN03 solution for 1 hour; .and Osterizer for 30 seconds. This washed in a I-percent NaOH solu­ gave fairly good separation of the tion. No maceration occurred. fibers. Variations of this method 7. Strips of culm 2 by 2 by 25 that were tried consisted of using mm. (approximately) were im­ pressures ranging from 5 to 15 mersed in a mixture consisting of p.s.1.; soaking for 3 to 4 days; equal volumes of glacial acetic dispersing in the Osterizer for up acid and 10-percent Na~O!! (sub­ to 45 seconds. stituted for H 2 0!!) for 48 hours at 60° C. (3). This treatment gave incomplete fiber separation. Exploratory Pulping Studies S. About 1 gram of small strips of Cooking conditions and results culm were soaked 3 days at room of exploratory treatments were as temperature in a 1: 1 mixture of a follows: -i-percent nitric acid plus 5-per­ 1. Cooking in water only at tem­ cent chromic acid; then heated to peratures of 160 0 to 170 0 C. for 60" C. for 3 hours. This treat­ 1, 2, and 3 hours softened the ment produced mtle change in the bamboo slightly but did not pulp culm strips. it. Yields (cooked bamboo) of the 9. About 5 grams of internodal 2- and 3-hour cooks were 79 and strips 2 by 2 by 25 mm. (approxi­ 74 percent, respectively. The hy­ mately) were covered with a 10­ drolyzate was slightly acid. percent NaOH solution in a 2. Cooking with .a 0.75-percent Mason jar and heated at 15 p.sj. solution of Na~C03 (equivalent to in a pressure cooker for 18 min­ 2 percent of N a 2 0 on basis of utes, then allowed to cool slowly moisture-free bamboo material) for 30 minutes. The NaOH solu­ at a temperature of 150 0 to 165 0 tion was poured off, the strips C. for 1.5 hours did not soften the ,vere washed, and then dispersed bamboo and resulted in a 98-per­ in a Waring Blendor for about 3 cent yield of cooked bamboo. minutes. This method gave a 3. Cooking with various concen­ fairly complete maceration of trations of NaOH for 1.5 hours at strips without excessive fiber temperatures of 150 0 to 160 0 C. breakage. failed to pulp the bamboo. Results 10. Nodal strips were subjected are shown in table 9. to the same treatment as the in­ TABLE 9.-Result!! of cooking bamboo at ternodal strips described in the 0 150 to 160 0 C. in .~tated cOllct)ntl'(l­ foregoing method, but the boiling tions of NaOH at 15 p.s.i. was extended to 30 minutes. This was followed by 2 Nn:O on days of soaking in distilled water Concen- basis of Yield oC pH oC trdtion moisture- cooked hydrolyzate (three water changes), and finally oCNaOH Cree bamboo bamboo by dispersing in an Osterizer for ! 30 seconds. The nodal splinters Perctml Percent 1.36_•••••--' 3.6 92 5.6 proved more resistant than the 1.90,, _____ . _j 5.3 90 6.5 2.40______6.6 90 7.8 internodal ones. 2.50_.__ •_•• 6.8 85 9.0 11. Strips were cut from a single ,. node, covered with 10-percent NaOH, heated at 15 p.s.i. for 30 4. Cooking in two stages.-The minutes, soaked in distilled water treatment was similar to that de­ 5 days with three changes of scribed by Raitt (10). First FIBER AND PAPERMAKING CHARACTERISTICS OF BAMBOO 19 stage: Bamboo was cooked at tem­ alkali as N~O (equivalent to 18.7 0 0 peratures of 100 to 110 C. for percent N~O on moisture-free 2.0 hours with 1.9-percent NaOH material) at temperatures of 145 0 using the hydrolyzate from pre­ to 150 0 C. for 1.5 hours. The final vious cooks fortified with addi­ pH was 11.9. These procedures tional N aOH until the final liquor produced a 'Pulp yield of 49 per­ contained 6.1 percent Na2 0 (on cent, and the bamboo was well the basis of moisture-free mate­ pulped. This two-stage cook was rial) . The final pH was 9.2. applied to several species of Second stage: Bamboo was cooked bamboo with similar results in with kraft white liquor composed which yields ranged from 40 to of 50 grams per liter of active 50 percent.

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