Abstract
The global increasing consumption of thermoplastic such as polyethylene and polypropylene has caused the generation of enormous amount of polymeric waste that are a challenge for solid waste management and represents a severe polluting agent, mainly for the marine life. Mechanical recycling is an important alternative to decrease the volume of polymeric waste. However, the mixture of different thermoplastic and other materials on the same object depreciates the properties of the recycled polymer due to the formation of immiscible blends. The aim of this study has been to evaluate the recycling of the post-industrial low-density polyethylene waste (LDPE waste) in presence of polypropylene using thermomechanical processing and thermochemical treatment of the material. For it, blends of LDPE waste and virgin polypropylene (PP) containing until 30 wt% of PP has been prepared with incorporation of zeolite ZSM-5 and Ziegler–Natta catalysts and submitted to the thermal treatment under controlled conditions of temperature and nitrogen flow. The results show the action of zeolite catalyst as modifier of the polymeric structure during step of the thermomechanical processing of the material. The catalysts have caused considerable changes on properties of the LDPE/PP blends, depending of the experimental conditions. The treatment of polymeric waste in presence of catalyst presents potential for recycling of polymeric materials with high contamination by other polymers and can generate recycled materials with improved properties.
Similar content being viewed by others
References
Herbort AF et al (2018) Alkoxy-silyl induced agglomeration: a new approach for the sustainable removal of microplastic from aquatic systems. J Polym Environ 26:4258–4270
Conceição MM et al (2018) Waste in Portugal—an analysis of plastic waste. Res Soc Dev 7(8):1–7
Song SF et al (2018) Facile synthesis of ethylene-propylene fully alternating copolymer and comparison with random copolymer of similar composition. J Appl Polym Sci 135(7):45816
Geyer R, Jambeck JR, Law KL (2017) Production, use, and fate of all plastics ever made. Sci Adv 3:e-1700782
Kumar S, Panda AK, Singh RK (2011) A review on tertiary recycling of high-density polyethylene to fuel. Res Conserv Recycl 55(11):893–910
Lerici LC, Renzini MS, Pierella LB (2015) Chemical catalyzed recycling of polymers: catalytic conversion of PE, PP and PS into fuels and chemicals over H-Y. Proc Mater Sci 8:297–303
Garcia JM, Robertson ML (2017) The future of plastics recycling chemical advances are increasing the production of polymer waste that can be recycled. Science 358(6365):870–872
Faraca G, Martinez-Sanches V, Astrup TG (2019) Environmental life cycle cost assessment: recycling of hard plastic waste collected at Danish recycling centres. Res Conserv Recycl 143:299–309
Siddiqui MN (2009) Conversion of hazardous plastic wastes into useful chemical products. J Hazard Mater 167(1–3):728–735
Barbarias I et al (2015) Catalytic cracking of HDPE pyrolysis volatiles over a spent FCC catalyst. Chem Eng Trans 43:2029–2034
Lin YH et al (2011) Recycling of dual hazardous wastes in a catalytic fluidizing process. Catal Today 174(1):37–45
De Marco I et al (2009) Pyrolysis of the rejects of a waste packaging separation and classification plant. J Anal Appl Pyrol 85(1–2):384–391
Pacheco Filho JGA et al (2005) Thermo gravimetric kinetics of polypropylene degradation on ZSM-12 and ZSM-5 catalysts. Catal Today 107–108:507–512
Kaminsky W, Zorriqueta IJN (2007) Catalytical and thermal pyrolysis of polyolefins. J Anal Appl Pyrol 79(1):368–374
Donaj PJ et al (2012) Pyrolysis of polyolefins for increasing the yield of monomers' recovery. Waste Manage 32(5):840–846
Lin YH et al (2004) Catalytic degradation of high density polyethylene over mesoporous and microporous catalysts in a fluidised-bed reactor. Polym Degrad Stab 86(1):121–128
Gu J, Xu H, Wu C (2014) The effect of benzoil peroxide and divinyl benzene on the properties of cross-linked recycled polyolefin blends. J Macromol Sci B 53(12):1777–1785
Mourad AHI (2010) Thermo-mechanical characteristics of thermally aged polyethylene/polypropylene blends. Mater Des 31:918–929
Graziano A, Jaffer S, Sain M (2019) Review on modification strategies of polyethylene/polypropylene immiscible thermoplastic polymer blends for enhancing their mechanical behavior. J Elast Plastic 51(4):291–336
Moreno DDP, Hirayama D, Saron C (2018) Accelerated aging of pine wood waste/recycled LDPE composite. Polym Degrad Stab 149:39–44
ASTM D 638 (2014) Standard test method for tensile properties of plastics, Barr Harbor Drive, West Conshohocken, USA
ASTM D256 (2014) Standard test method for determining the Izod pendulum impact resistance of plastics, Barr Harbor Drive, West Conshohocken, USA
Kong Y, Hay JN (2002) The measurement of the crystallinity of polymers by DSC. Polymer 43:3873–3878
Ujhelyiova A et al (2019) Polypropylene crystallisation in the presence of inorganic additives. Fibres Text East Eur 27(2):30–39
ASTM 1238 (2013) Standard test method for melt flow rates of thermoplastics by extrusion plastometer, Barr Harbor Drive, West Conshohocken, USA
Al-Salem SM et al (2017) Thermal degradation kinetics of virgin polypropylene (PP) and PP with starch blends exposed to natural weathering. Ind Eng Chem Res 56:5210–5220
Martin S et al (2011) A three-phase microstructural model to explain the mechanical relaxations of branched polyethylene: a DSC, WAXD and DMTA combined study. Colloid Polym Sci 289:257–268
Moreno DDP, Saron C (2018) Influence of compatibilizer on the properties of low-density polyethylene/polyamide 6 blends obtained by mechanical recycling of multilayer film waste. Waste Manage Res 36(8):729–736
Acknowledgements
The authors would like to thank the Fábrica Carioca de Catalisadores and Valfilm Ltda for supplying the materials as well as the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior-CAPES and Fundação de Amparo à Pesquisa do Estado de São Paulo-FAPESP (Proc. 2017/05851-0) for their financial support.
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
de Camargo, R.V., Saron, C. Mechanical–Chemical Recycling of Low-Density Polyethylene Waste with Polypropylene. J Polym Environ 28, 794–802 (2020). https://doi.org/10.1007/s10924-019-01642-5
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10924-019-01642-5