Effects of the compatibilizer PE‐g‐GMA on the mechanical, thermal and morphological properties of virgin and reprocessed LDPE/corn starch blends

Abstract

The effects of the compatibilizer polyethylene grafted with glycidyl methacrylate (PE-g-GMA) on the properties of low-density polyethylene (LDPE) (virgin and reprocessed)/corn starch blends were studied. LDPE (virgin and reprocessed)/corn starch blends containing 30, 40 and 50 wt% starch, with or without compatibilizer, were prepared by extrusion and characterized by the melt flow index (MFI), tensile test, dynamic mechanical analysis (DMTA) and light microscopy. The addition of starch to LDPE reduced the MFI values, the tensile strength and the elongation at break, whereas the modulus increased. The decreases in the MFI and tensile properties were most evident when 40 and 50 wt% starch were added. Blends containing 3 wt% PE-g-GMA had higher tensile strength values and lower MFI values than blends without compatibilizer. Light microscopy showed that increasing the starch content resulted in a continuous phase of starch. Figure 12. Light micrographs for virgin LDPE/starch blends: (a) 70/30; (b) 60/40; (c) 50/50 (30Â). LDPE/corn starch blends 317

Compatibilization of low‐density polyethylene/cassava starch blends by potassium persulfate and benzoyl peroxide

“…With initiators, the modulus increased from 214 MPa to a maximum of 508 MPa in the blend containing 50 wt % starch. The increase in the modulus due to the addition of initiators to these blends was greater than that for the LDPE/corn starch blends compatibilized with polyethylene grafted with glycidyl methacrylate, 10 by which the modulus increased from 240 to 300 MPa. The tensile strength also increased with the addition of initiators.…”

“…Young's modulus increased whereas the tensile strength (stress at break) and elongation at break decreased as the amount of starch increased, as reported by many researchers. 3,4,6,10,24,30 Superior modulus and tensile strength were displayed by the blends containing initiators. Among the blends without initiators, the maximum modulus, 261 MPa, appeared for the blend containing 60 wt % starch.…”

“…[27][28][29][30][31][32] To increase the compatibility of LDPE/starch blends, modified or nonnative starch has been used, such as pregelatinized starch, 11 crosslinked starch, 14 octanoated starch, 18,19,33 starch acetate, 20 hydropropylated starch, 21 and phthalated starch. 34 Polyethylene graft copolymers have been widely used as compatibilizers with other polymers; they include polyethylene grafted with maleic anhydride (PE-g-MA), 1,3,5,6,17,24,25,35,36 polyethylene grafted with glycidyl methacrylate, 10,27 LDPE grafted with dibutyl maleate, 31 LDPE grafted with itaconic acid, 32 an ethylene/acrylic acid copolymer, 16,37 and polyethylene grafted with styrene-co-maleic anhydride polymer. 38 Other polymers used as compatibilizers include an ethylene/vinyl acetate copolymer, 2 an ethylene/vinyl alcohol copolymer, 28 and a functionalized metallocene copolymer.…”

Estudo das propriedades e biodegradabilidade de blendas de poliéster/amido submetidas ao ataque microbiano

“…Os plásticos têm papel fundamental na sociedade moderna, mas devido ao fato de algumas aplicações destes materiais serem de descartabilidade muito rápida, associado à grande dificuldade de degradação no ambiente, podendo demorar séculos para se degradar e ocupando grande volume na área dos aterros, têm despertado fortes preocupações nos dias atuais [1][2][3][4][5][6][7] . O aumento no interesse científico pela área ambiental, atraído pelo crescimento explosivo do consumo de polímeros ou plásticos e pela disposição final destes resíduos sólidos urbanos, tem tornado cada vez mais necessária, a produção de substitutos ambientalmente sustentáveis, importantes no gerenciamento de resíduos, os chamados polímeros ou plásticos ambientalmente degradáveis (PADs), compostos por um vasto grupo de materiais poliméricos, naturais e sintéticos, que sofrem alterações químicas sob a influência de fatores ambientais 8 .…”

Thermal, Mechanical and Antibacterial Properties of Ldpe/Starch Bio-Based Polymer Blends for Food Packing Applications

“…Because of its hydrophobicity, high molecular weight, and absence of functional groups susceptible to microorganisms, it is hard to degrade under normal composting conditions, and the ever-increasing waste of this plastic constitutes a major environmental risk [3,11]. The melt blending of LDPE with a biopolymer such as starch makes it biodegradable [3,[12][13][14][15]. Starch is a biopolymer derived from renewable resources such as corn, wheat, rice, and potato, and has a renovated interest to form biodegradable plastics due to its lower price, wider availability, higher purity, non-toxicity, and very favorable environmental profile.…”