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International Journal of Advances in Science Engineering and Technology, ISSN(p): 2321 –8991, ISSN(e): 2321 –9009 Vol-7, Iss-1, Spl. Issue-2 Mar.-2019, http://iraj.in COMPARATIVE STUDY OF LIFE CYCLE ASSESSMENT OF POLYPROPYLENE AND POLYLACTIC ACID FOR FOOD PACKAGING

1SYAMIM FAUZI, 2HAZLEEN ANUAR

1,2Manufacturing and Material Engineering IIUM Malaysia E-mail: [email protected], [email protected]

Abstract - Synthetic polymers caused depletion of the petroleum. Development of PLA as food packaging is frequently done to reduce the environmental impact due to its characteristic of easily degraded. Cradle-to-grave analysis of PLA indicates that even though PLA packaging is easy to degrade, it will still be considered as waste after disposal. However, biodegradability of PLA enabled the cradle-to-cradle analysis to be made where no unwanted excess material produced as it can be recuperated or reused as the packaging decomposes into nutrients. System boundary is first developed. PLA gives lesser GWP where PP gives 203.0 Kg CO2 eqv. Due to implementation of cradle-to-cradle, the GWP value of PLA is reduced to 161.37 Kg CO2 eqv from 164.6 Kg CO2 eqv. AP value of PLA is lower than PP packaging with amount of 4.89 x -1 -1 10 Kg SO2 eqv and 4.89 x 10 Kg SO2 eqv for PLA. PP packaging gives lesser environmental impact through ODP and EP with 7.09 x 10-12 Kg CFC-11 eqv and 1.10 x 10-4 Kg P eqv each as compared to PLA with 6.22 x 10-10 Kg CFC-11 and 1.79 x 10-4 Kg P eqv. As the major contributor towards the environmental impact is GWP which covered about 97% over others, PLA packaging gives better environmental impact as compared to PP packaging.

Keywords - Life Cycle Assessment, Cradle-to-Cradle, Polypropylene, Polylactic acid, Food packaging, Environmental Impacts

I. INTRODUCTION terms of (GWP)[4]. To date however, there is none of the researchers have Synthetic polymers are well known in many human conducted cradle-to-cradle assessment on polylactic activities along with industrial development. These acid as it is biodegradable that decompose into artificial substances are basically made up from nutrients that help in new crop production [5]. Thus, petroleum which define the non-degradable properties the aim of this study is to quantify the environmental that cause harm and problem to the environment impacts on food packaging of polypropylene (PP) and which is not subtle for temporary use [1]. As a polylactic acid (PLA)fabricated.Both PP and PLA countermeasure to the environmental problems such were assessed using GaBi Software. Cradle-to-gate as towards the , researchers are system boundary was developed for PPwhereas consistently developing and enhancing the properties cradle-to-cradle system was developed for PLA.The of the biodegradable polymer of PLA to make it environmental impact quantified were global competitive with other synthetic polymers which are warming, depletion, and well known for their good mechanical properties such acidification. as PP. Environmental impacts can be assessed by tool of Life Cycle Assessment (LCA) as II. METHODOLOGY it is an approach which is used to evaluate environmental impacts potential. Interpretation of 2.1. Definition of Scope LCA comprises the assessment of the environmental Scope of cradle-to-cradle is used for the PLA and impacts starting with the early stage of the product cradle-to-grave for PP.The raw pellets of both PP and that consists of raw materials towards the end of the PLA were obtained from suppliers accordingly where product‟s life [2]. In order to develop LCA, system it has been transported to the manufacturing plant that boundary must be identified. System boundary is what later on transported to consumer defined as use phase defines the unit processes that need to be included in and lastly to the where landfill site for PLA the modeled system. There are different types of scope serves as a nutrients settling. that defined the system boundary which are cradle-to- 2.2. Functional Unit for Production of Packaging grave, cradle-to-gate and gate-to-gate in LCA [3]. Functional unit used for producing food packaging of Cradle-to-cradle assessment on the other hand defined both PP and PLA was 50 units where the weight for as another sustainability tool with certification system each unit of PLA food packaging is defined to be that provides an informative methodology. As 0.0106 kg while the weight for each unit of PP food compared to LCA scopes, cradle-to-cradle assessment packaging is 0.0073 kg. provides a definitive analysis that covers a closed 2.3 Transportation system as the status of the resources is For this project, PP required only land transportation maintained.PLA packaging gives lesser environmental of a car as it is obtained from Penang while PLA impact compared to other synthetic packaging in required air and land transportation as it is obtained

Comparative Study of Life Cycle Assessment of Polypropylene and Polylactic Acid for Food Packaging

37 International Journal of Advances in Science Engineering and Technology, ISSN(p): 2321 –8991, ISSN(e): 2321 –9009 Vol-7, Iss-1, Spl. Issue-2 Mar.-2019, http://iraj.in from Nature Works located in China. PP required an III. RESULTS AND DISCUSSION estimated distance of 276 km from supplier to manufacturing plant. For PLA, the distance from the 3.1. Global Warming Potential supplier is estimated to be 4004 km of airway and The result of GWP for PP is shown in Figure 3. The 77 km of roadway while the distance for transporting presence of recovery section in the plotted graph the used product to the landfill site for both PP and indicated the material recovery of PLA due to PLA are estimated to be 10 km. implementation of cradle-to-cradle method in assessing the environmental impact. It can be seen 2.4 Electricity that GWP of PP is higher compared to PLA where the For PP, the electrical energy was only used for the amount of GWP for PP is 203 Kg CO2 eqv. The fabrication of the food packaging through amount of GWP of PLA is reduced from 164.6Kg compression molding. PLA required higher electrical CO2 eqv to 161.037 Kg CO2 eqv due to the energy due to drying and compression molding implementation of cradle-to-cradle method of PLA processes. For PP, 847.22 MJ amount of electrical where the material recovery is considered. This can consumed while for PLA, 10.80 MJ for drying and be seen as similar to the study made by (GPI, 2007) 678.96 MJ was used for compression molding where cradle-to-cradle results in reduction of global process. warming potential.Manufacturing process of compression molding for PP and extra process of 2.5 Life Cycle Impact Assessment drying for PLA is the major cause of global warming Potential environmental impact of Global Warming for both PP and PLA that indicates the major cause of Potential (GWP), Depletion Potential global warming for food packaging production is due (ODP), Eutrophication Potential (EP) and to the usage of electricity followed by transportation, Acidification Potential (AP) with unit of Kg CO2 eqv, obtaining raw pellets which include the production of Kg CFC-11 eqv, Kg P eqv and Kg SO2eqv each were raw pellets and lastly deposition to landfill. The assessed and interpreted as the system boundary been process of obtaining that includes production of raw developed. The impact was analysed up to the pellets for PLA is lesser which 0.311 Kg CO2 eqv midpoint level that covers the environmental problem over PP which is 0.718Kg CO2 eqv. This is due to the that were positioned between the inventory and presence of carbon dioxide, nitrous oxide, sulphur endpoint level. The impacts were assessed using hexafluoride, and greater gas emission as ReCipe (1.08) as LCIA method provided by the compared to PLA that contributed to GWP. Greater GaBisoftware.Figure 1 and Figure 2 show the system amount of GWP contributed in producing PP boundary developed for both PP and PLA food compared to PLA was due to the process of packaging. extraction from petroleum that required higher amount of energy used thermally and electrically where production of PP granules gives high GWP than biodegradable plastics [7]. Landfilling activity of PP is simply lesser than PLA due to composting reaction as high amount of methane is produced by bacterial decomposition when an organic material of PLA is disposed towards landfill [8]. However, due to cradle-to-cradle implementation, the amount of greenhouse gases are sequestered and absorbed by the plants as the new material are recovered by new crop production that later on deduce the overall amount of global warming to 161.037 Kg CO2eqv.

Figure 1. Developed system boundary for PP in the GaBisoftware

Figure 2. Developed system boundary for PLA in the GaBi software Figure 3. Global Warming Potential of PP and PLA packaging

Comparative Study of Life Cycle Assessment of Polypropylene and Polylactic Acid for Food Packaging

38 International Journal of Advances in Science Engineering and Technology, ISSN(p): 2321 –8991, ISSN(e): 2321 –9009 Vol-7, Iss-1, Spl. Issue-2 Mar.-2019, http://iraj.in 3.2. Potential required in order to shape PP packaging. Excess Figure 4 shows the ODP value in producing PP and emission of phosphorus and phosphates caused by PLA packaging. Process of obtaining raw pellets greater electricity generation to support electrical serves as a major contributor to ozone depletion as demand will induce environmental problem due to the ODP value in producing PLA food packaging is high coal combustion[12].Both polylactic acid and 6.03 x 10-10 Kg CFC-11 eqv with no ozone depletion polypropylene, process of producing PLA produces caused by producing PP pellets. higher EP value of 4.51 x 10-5Kg P eqv while PP gives3.52 x 10-5 Kg P eqv. This is due to due to high This is due to the usage of fertilizers and in chemical oxygen demand raw [13][14]. growing the crops and chemical processing that is required in converting the organic material into PLA while no pesticides and fertilizers needed in producing PP. Transportation of PLA provides a higher ODP value of 1.51 x 10-11 Kg CFC-11 due to further distance travelled in transporting PLA that required higher consumption amount of in system as compared to PP with 2.23 x 10-13 Kg CFC-11. Refrigerant in air conditioning system emitted mainly HFCs and CFCs as it is harmful to the atmosphere [9]. ODP value contributed by electricity consumption in producing PLA is lesser as compared to PP. Large electrical consumption leads to high usage of halon gases and fire suppressant [10].

Figure 5. Eutrophication Potential of PP and PLA packaging

3.4. Acidification Potential Acidification potential of PP and PLA food packaging are shown in Figure 6. Manufacturing process of PP packaging serves as a major contributor to acidification as the AP value of manufacturing PP -3 packaging is 2.05 x 10 Kg SO2 eqv which is higher than manufacturing process of PLA food packaging -3 with 3.83 x 10 Kg SO2 eqv. This is because manufacturing of PP packaging required relatively higher amount of electricity than PLA packaging. Acidification is related to the emission of gases of nitrogen oxide, nitrogen dioxide, and sulphur dioxide where nitrogen dioxide emission

Figure 4. Ozone depletion Potential of PP and PLA packaging serves as the major contributor towards environmental impact of acidification for both PP and 3.3. Eutrophication Potential PLA as much as 57% for PP and 58% for PLA while Eutrophication potential of PP and PLA food sulphur dioxide has been the second major packaging are shown in Figure 5. Landfilling activity contributor towards acidification of 43% for PP and serves as a major contributor to eutrophication as the 42 % for PLA packaging as according to study made EP value of landfilling activity of PLA food by Nizam et. al (2013)[15], NO2 gases emission packaging is 9.47 x 10-5Kg P eqv which is higher produced about 27% from power plant sector in than landfilling activity of PP food packaging with Malaysia and about 48% of sulphur dioxide 2.09 x 10-5 Kg P eqv. compared to other sector. Process of obtaining PLA -3 This is due to the breakdown of PLA food packaging produced higher AP value of 3.83 x 10 Kg SO2 -3 into nutrients that act as fertilizers of for farming eqvcompared to PP of 2.05 x 10 Kg SO2 eqv. This is activity of the plants used that cause eutrophication because, PLA involves in crops production that towards the water bodies [11]. PP produces higher EP required amount of nutrients and fertilizers that help value which is in plant growth that causes the amount of 4.37 x 10-5Kg P eqv as compared to PLA of 5.57 x10- acidification substances to be absorbed by the oceanic 7 Kg P eqv for drying and 3.50 x 10-5Kg P eqv for water [16]. Composting biodegradable packaging compression moldingas more electrical energy is leads to intensive oxygen breakdown process [17].

Comparative Study of Life Cycle Assessment of Polypropylene and Polylactic Acid for Food Packaging

39 International Journal of Advances in Science Engineering and Technology, ISSN(p): 2321 –8991, ISSN(e): 2321 –9009 Vol-7, Iss-1, Spl. Issue-2 Mar.-2019, http://iraj.in PS clamshell containers using LCA methodology,” J. Clean. Prod., vol. 17, no. 13, pp. 1183–1194, 2009. [5] J. H. Song, R. J. Murphy, R. Narayan, and G. B. H. Davies, “Biodegradable and compostable alternatives to conventional plastics,” Philos. Trans. R. Soc. B Biol. Sci., vol. 364, no. 1526, pp. 2127–2139, 2009. [6] U. P. Glass, M. Syndicate-firozabad, G. Manufacturers, and G. Manufacturers, “Life Cycle Assessment of „ Container Glass and Comparison with Alternate Packaging Mediums ( PET , Beverage Carton , Aluminum Can and Pouch ),‟” pp. 1–13, 2013. [7] W. J. Groot and T. Borén, “Life cycle assessment of the manufacture of lactide and PLA biopolymers from sugarcane in Thailand,” Int. J. Life Cycle Assess., vol. 15, no. 9, pp. 970–984, 2010. [8] H. Yagi, F. Ninomiya, M. Funabashi, and M. Kunioka, Figure 6. Acidification Potential of PP and PLA packaging “Anaerobic Biodegradation of Poly (Lactic Acid) Film in Anaerobic Sludge,” J. Polym. Environ., vol. 20, no. 3, pp. 673–680, 2012. CONCLUSIONS [9] B. O. Bolaji and Z. Huan, “Ozone depletion and global warming: Case for the use of natural refrigerant - A review,” As the system boundary have been developed, GWP, Renew. Sustain. Energy Rev., vol. 18, pp. 49–54, 2013. [10] B. Atilgan and A. Azapagic, “Life cycle environmental ODP, EP and AP were assessed where global impacts of electricity from fossil fuels in Turkey,” J. Clean. warming provides highest impact score with Prod., vol. 106, pp. 555–564, 2015. significant potential for both PP and PLA packaging [11] V. N. de Jonge, M. Elliott, and E. Orive, “Causes, historical as compared to other impact. GWP for PP is 203 kg development, effects and future challenges of a common environmental problem: eutrophication,” Hydrobiologia, vol. CO2 eqv while 162.4 kg CO2 for PLA after 475–476, no. 1, pp. 1–19, 2002. considering cradle-to-cradle assessment. [12] R. Wang, Y. Balkanski, O. Boucher, P. Ciais, J. Peñuelas, Cradle-to-grave of PLA packaging provides lesser and S. Tao, “Significant contribution of combustion-related emissions to the atmospheric phosphorus budget,” Nat. GWP of 166.49 kg CO2 as compared to cradle-to- Geosci., vol. 8, no. 1, pp. 48–54, 2015. grave of PP packaging. However, cradle-to-cradle of [13] I. Heidelberg, “Life Cycle Assessment of Poly Lactide ( PLA PLA proven that GWP of PLA could be reduced once ),” no. July, p. 168, 2006. more. This concludes that PLA packaging gives [14] S. Papong et al., “Comparative assessment of the lesser environmental impact than PP as GWP covered environmental profile of PLA and PET drinking water bottles from a life cycle perspective,” J. Clean. Prod., vol. 65, pp. about 97% of overall environmental impacts. 539–550, 2014. [15] S. Nizam, S. Muhammad, M. Abdullah, and N. A. Newaz, REFERENCES “Emissions : Sources , Policies and Development in Malaysia,” Int. J. Educ. Res., vol. 1, no. 7, pp. 1–12, 2013. [1] M. Klar, D. Gunnarsson, A. Prevodnik, C. Hedfors, and U. [16] A. Detzel, B. Kauertz, and C. Derreza-Greeven, “Study of the Dahl, “Report Everything you (don‟ t) want to know about Environmental Impacts of Packagings Made of plastics,” 2014. Biodegradable Plastics,” Environ. Res. Fed. Minist. Environ. [2] M. M. Khasreen, P. F. G. Banfill, and G. F. Menzies, “Life- Nat. Conserv. und Nucl. Saf., p. 118, 2013. cycle assessment and the environmental impact of buildings: [17] E. Sebille, C. Spathi, and A. Gilbert, “The ocean plastic A review,” Sustainability, vol. 1, no. 3, pp. 674–701, 2009. pollution challenge: towards solutions in the UK,” Imp. Coll. [3] J. B. Guinée, “Handbook on Life Cycle Assessment,” ECO- London Grantham Inst., vol. Briefing p, no. 19, p. pp 1-16, EFFICIENCY Ind. Sci. Ser., vol. 7, p. 692, 2002. 2016. [4] S. Madival, R. Auras, S. P. Singh, and R. Narayan, “Assessment of the environmental profile of PLA, PET and

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Comparative Study of Life Cycle Assessment of Polypropylene and Polylactic Acid for Food Packaging

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