In this study, poly(ethylene terephthalate)‐
- NSF-PAR ID:
- 10385099
- Date Published:
- Journal Name:
- ACS Macro Letters
- Volume:
- 11
- ISSN:
- 2161-1653
- Page Range / eLocation ID:
- 1396 to 1402
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Management of the plastic industry is a momentous challenge, one that pits enormous societal benefits against an accumulating reservoir of nearly indestructible waste. A promising strategy for recycling polyethylene (PE) and isotactic polypropylene ( i PP), constituting roughly half the plastic produced annually worldwide, is melt blending for reformulation into useful products. Unfortunately, such blends are generally brittle and useless due to phase separation and mechanically weak domain interfaces. Recent studies have shown that addition of small amounts of semicrystalline PE- i PP block copolymers (ca. 1 wt%) to mixtures of these polyolefins results in ductility comparable to the pure materials. However, current methods for producing such additives rely on expensive reagents, prohibitively impacting the cost of recycling these inexpensive commodity plastics. Here, we describe an alternative strategy that exploits anionic polymerization of butadiene into block copolymers, with subsequent catalytic hydrogenation, yielding E and X blocks that are individually melt miscible with PE and i PP, where E and X are poly(ethylene- ran -ethylethylene) random copolymers with 6 wt% and 90 wt% ethylethylene repeat units, respectively. Cooling melt blended mixtures of PE and i PP containing 1 wt% of the triblock copolymer EXE of appropriate molecular weight, results in mechanical properties competitive with the component plastics. Blend toughness is obtained through interfacial topological entanglements of the amorphous X polymer and semicrystalline i PP, along with anchoring of the E blocks through cocrystallization with the PE homopolymer. Significantly, EXE can be inexpensively produced using currently practiced industrial scale polymerization methods, offering a practical approach to recycling the world’s top two plastics.more » « less
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Abstract We have investigated melt blending approaches to interfacial localization of few‐layer graphene in cocontinuous polymer blends with polyethylene as one of the components. When linear low‐density polyethylene (LLDPE)/polypropylene (PP) or high‐density polyethylene (HDPE)/polylactic acid (PLA) and graphene were mixed all together, graphene preferred polyethylene over PP or PLA. When PP and graphene were premixed and blended with polyethylene, some graphene was trapped at the blend interface but not enough to cover the large interfacial area. In contrast, an ultralow electrical percolation was achieved (< 0.1 vol%) in HDPE/PLA blend due to smaller interfacial area. In another approach, polystyrene was added as a tertiary minor component to HDPE/PLA blends. This continuous interfacial layer containing graphene led to a low electrical percolation threshold (< 0.2 vol%). From these investigations, we suggest general ways to reduce a percolation threshold by kinetic control of the morphology of cocontinuous polymer blends.
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2019 ,57 , 281–290
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1021/acsmacrolett.2c00601
