Reaction Injection Moulding of Syndiotactic Polystyrene: the Effect of Reaction Parameters on Monomer Conversion and Polymer Properties
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Reaction Injection Moulding of Syndiotactic Polystyrene: The Effect of Reaction Parameters on Monomer Conversion and Polymer Properties Colin Li Pi Shan A ehesis subrnitted to the Department oÇChemistry in conformity with the requirements for the degree of Mas ter of Science (Engineering) Queen's University Kingston, Ontario, Canada September 1997 copyright O Colin Li Pi Shan, 1997 National Library Bibliothèque nationale I*I of Canada du Canada Acquisitions and Acquisitions et Bibliographie Services services bibliographiques 395 Wellington Street 395. rue Wellington OttawON K1AON4 Ottawa ON K1A ON4 Canada Canada The author has granted a non- L'auteur a accordé une licence non exclusive licence allowing the exclusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loan, distribute or sel1 reproduire, prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la fome de microfiche/^ de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur consenre la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fkom it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. Abstract The primyy objective of this research wu to investigate the narure of the conversion limitation in the developrnent of a novel syndionctic polystyrene (sPS) rel-ctioii injection mouldiiig @Ili) pmcess. By vqing the reaction p*Lu;uIieteeof the estent of mising, reaction rime wd mould wall tempenture, the effects on the monorner conversion ünd polymer properties were determinrd. Cdiztng a two component medlocene cataiyst system comprised of Cp*TiuMe~and B(Cfi F-),3, styrene monomer \vas polmerized in bulk in a specially constructed RIM app;irJtus to produce syndior~ctic polysryrene. Ir \vas obsemed diat the reÿction wÿs highly esothecmic md that hi& conversions to hi$? syndiotactic polymer occurred. It w:is found tliat r-ing the mould w;Jl tempenture Ii:id the largest effecr on tlic polynerization. .At the lower mould tempemures, increases ùi the conversion were fouiid. At Liotli the highest and lowest rempenture estrernes snidied, it wvs discovered that die polymer proprrries detecior~ted. In studying different reaction times, it was found t1i:ir the catalysr activity ç:ui I)c sustaîned for longer duntion to increase the conversion while m~iiitaiiiilgthe polyner propertics. .it short reaction times the polyrnerizarion occurs quite mpidly -and hi& convenioiis cmbe diievcd within minutes. Vsqing the estent of misuig had little to rio effect on die coiiversion and polymrr properries. In dl die conditions snidied to reduce an- difhsion or temperature limirritions, a limitirig conversion w;is sdl reached. Investigations into the cystdlirie iiamre of the polymer revealed thac the coiivenion limitation of the polymerïzation may be due to the enrrapmenr of styrene monorner widiin die c~srailùieregioiis of sPS. This entrapmenr is hypodiesized to occur via a styrene-sPS rnolecuhr cornples which is related to the hel ical conformations of s yiidio tactic pol ystyrene. Acknowledgements 1 would like to thank Dr. Vi.E. Baker for his guidance and supervision, riot onlv in the aspects of the project but as educator in the aJLiing of Engmeering Cliernists. 1 dso esrend my thanks CO both Dr. M.F. Cunningham and Dr. K.E. Russell whose researcli esperieiice ïiid suggestions were induable. -Yso, 1 musr acknowledge Dr. MC. Baird aid his Iab goup fr)r providing the srarting materials and technicd expertise for the cntalysc sydieses. My thmks, dso spreads out to the members of the Baker L;lb who suppocted my frustrarions ÿnd triumphs while making the esperience enjoyable. Specid diÿnks so to D. (Iuk :uid S. Hojabr for helpfLl discussions and to Dr. T. Liu for his previous esperieiice -and assistance witli the ariaiyticd TG.% work. Lastly, 1 would like to express my sincere gr~titudeco rny Eimily hr alwïdys supporurig my endeavours. -4 special tvord is dso bestowed ro my friends, for the friendships 1 have treasured at Queen's. Table Of Contents Absuact Acknowledgements Table of Contents List of Figures List of Tables List of Symbols 1.0. Introduction Z.I. Syndiotaak Polysîyrene 1.1.1 Background to sPS 1.1.1.1 Properties of Polystyrene 1.1.1.2 Structud Polyrnorphism of sPS 1.1.2 Syndiospedic Polymerization O f Styrene 1.1.2.1 Cadysa and Mechanisms 1.1.2.2 Effect O t Po1ymeriz;ition Conditions on Catalyst ;ictivity ;ind Material Properties 1.1 .î.3 High Conversion Styrene Polymerizations 1.2 Con ven ti'onai Sryrene PoI'erÙatio~ 1.2.1 Thermÿl and Bulk Polymerization of Styrenr 1.2.2 Difhsion ControIIed Phenomena 3.3 MM Processing 1.3.1 Introduction to RIhI 1.3.2 Wh1 Processing Requirements 1.3.3 Previous studies of RIhl Processing of sPS 1.4 Auns ofdiis Study 2.0 Expetimental 2.2 Mateds 2.2 Metdocene Cacllyst Synthesis 2.2.1 Prepmtion O t Cp0Tihfe,Catdyst 2.2.2 Prepmtion of B(C,Fd, Cocatdyst 2.3 Reaction Injecrion MouidUIg PolymerUations 2.3.1 RliLl hlising =\pparatus 2.3.2 Rihl Technique 2.3.3 Temperature Monito~g 2.3.4 Esperimennl Studies 2.3.4.1 Prepolymerization of Styrene by Borne Coçaralys t 2.3.1.2 Benchmark Control Study 2.3.4.3 M.sing Study 2.3.4.4 Reaction Time Study 2.3.4.5 .\lould \Xd Tempemture Study 2.3.5 Rcsidual LIonomcr Loss/(:onversion Estimate Table of Contents Cont'd. 2.3.5.1 \Txuum Oven drying 2.3.5.2 Thermogravime tic rùidilysis 2.4 Charactenkarion of PS Polymers 2.4.1 Deterrnination of sPS/aPS Frxtions 2.4.2 Product Identification and Txticity Analysis 2.4.3 Determination of ThedProperties 2.4.4 Deterrnination of Molenilar Weight 2.4.5 Estimaaon ofsPS Crystdlinity and Identification of Crysnlline Forms 3.0 Results and Discussion 3.1. EstUnating the Monomer Conversion ofBulX-Pof'enZed RIM Samples 3.2 Control Smdy ofRIM Polperizations 3.2.1 Benchmark Reproducibility 3.2.2 Characteristics of RIhl Polystyrene 3.3 Effect ofilhkihg on the MM Poiymerization 3.3.1 Effect of Mising on Conversion 3.3.2 Eifect of hllxing on Material Properties 3.1 Effect of Theon the RIM Polymerization 3.4.1 Ef'fect of Retiction Tirne on Conversion 3.4.2 Effect of Reaction Tirne on Marerixi Pro perties 3.5 Effecrof Mouid Temperature on the MM Polymnkatio~ 3-51 Effect of Mould \Vail Temperature on Conversion 3.5.2 Effect of Mould W'dI Temperature on Materid Properties 3.6 Conversion Limirations of the Polymenkation 4.0 Conclusions 5.0 Recommendations and Future Work References Table of Contents Cont'd. Appendices and Curriculum Vitae Typicd TGA Therrnogm of sPS RIM Smple Randomized Experimentd Run List Borane Prepolymerization Smdy =HN&fR ofsPS 'H YhIR ofaPS 13cUiR of sPS NMR of aPS DSC Thermal Trace ofsPS Sample lilxing Study G: Reacuon Time Study H: Mould \Val1 Temperature S~dy 1: Crysnllinity Estimates of sPS Samples Curriculum Vitae List of Figures Fig. 1.1: Strucninl configurations of polysryrene Fig. 1.2.1: sPS zigzag and helical represenntions Fig. 1.2.2: Methods of obnining sPS ~xystdlineforms Fig. 1.2.3: Structurai representations of sPS-roluene molecular complrs Fig. 1.2.4: Representation of the entrapment of benzene molecules within sPS moie~vles Fig. 1.3.1: MeMi-coordinated insertion mechanism of styrene Fig. 1.3.7: P-hydrogen elimination reaction in styrene polymerizations Fig. lA.1: Styrene polymerimtion canlyzed by Cp'TiiLIe,/,LLiO Fig. 1-42 EFfect ofstyrene concentration on the monomer conversion Fig. 1.4.3: Effeect of increasing polymerizi~tiontime on the monomer conversion Fig. 1.4.4: EEeçt of increasing temperature on the monomer conversion Fig. 1.4.5: Variation of syndiotactic yield and melting point of sPS versus pol y merization temperature Fig. L.5.1: Thermal Initiation O ï Styrene Fig. 1.5.2: Chain Growth Propagation of Styrenr Fig. 1.6: Effect of Diffusion Controlled Temination Fig. 1.7: Schematic of a RIM process Fig.2.1: RIM hlishead Schematic Fig 2.2: RI,\;[ :lppariltus Setup Fig 23: Flowchart of the Ch~mcrerizationof RIM S:unples Fig 2.4: ' H SMR of mehine and methylene C region of polystyrenes Fig 2.5: 13 C SMR of phenyl C region of polystyrenes Fig 2.6: Eupanded inkued specaa of sPS smples in three differerent regions Fig 2.7: FTIR IR specn of sPS dis tinguis hing a and P çrystalline toms Fig 2.8: FTIR IR specm ot'sPS distinguishing 6 and y crystdline forms Fig. 3.1: Typicd sPS RNpolymerization reaction temperature pro file Fig. 3.3- 1: Effect of mixing method on the monorner conversion Fig 3.3.2: Effect of the mking method on the sPS fraction Fig. 3.4.1: EfFect of reaction time on the monomer conversion List Of Figures Cont'd. Fig. 3.4.2: Effect of reaction time on the sPS Enchon Fig. 3.4.3: Effect of reaction time on sPS ~vt.avg. molecular weight Fig. 3.4.4: Effect of reaction time on sPS num. iivg. rnolecular weight Fig. 3.5.1: 60 OC mould wdl temperature pro tile Fig. 3.5.2: 110 OC mould wdvall tempenture profile Fig. 3.5.3: O OC mould wdl temperature profile Fig. 3.5.4: -20 OCmould wdl tempenture profile Fi. 3.5: Effect oE mould 41temperature on the monomer conversion Fig. 3.5.6: Effect of mould dltemperature on the sPS haion Fig.