Miscibility and Biodegradation Behavior of Melt-Processed Blends of Bacterial Poly(3-Hydroxybutyrate) with Poly(Epichlorohydrin)

Abstract

The miscibility of melt processed blends of bacterial poly( 3-hydroxybutyrate) (PHB) with poly(epich1orohydrin) (PEC) is investigated over the whole range of compositions by means of differential scanning calorimetry, dynamic-mechanical analysis, and hot-stage optical microscopy. PHB and PEC are miscible in the melt in all proportions. After melt quenching, PHBIPEC blends show a single glass transition that linearly changes with composition between the Tgs of the pure components (PHB = 2OC, PEC = -21OC). At room temperature all PHB/PEC blends are partially crystalline, owing to crystallization of a constant fraction (58%) of the PHB present in each blend. A spacefilling spherulitic morphology develops upon blend crystallization from the melt. Isothermal crystallization measurements show that over the range of crystallization temperatures (4OOC < T, < 130OC) and compositions (20% < PEC < 80%) explored, the spherulite radial growth rate ( G ) decreases with increasing PEC content. Biodegradation experiments, carried out in activated sludge and in enzymatic solution (PHB-13 Copyright 0 1997 by Marcel Dekker, Inc.

Crystallization behavior and morphology of poly(propylene terephthalate) copolymers containing neopenthyl glycol moieties

“…A possible explanation for this trend of band spacing in the spherulites of PPT‐PNT copolymers is that the rejection of neopenthyl terephthalate comonomeric units from crystalline lamellae to an interlamellar amorphous region gives rise to stresses on the lamellar surfaces, resulting in a twisting characterized by a shorter period during crystallization. The observed decrement of band spacing is in line with earlier evidences that in polyesters and polyamides spherulite banding narrows in the presence of increasing amounts of a noncrystallizable component 47–52…”

Blendas de PHB e seus copolímeros: miscibilidade e compatibilidade

“…Blendas de PHB e elastômeros de epicloridrina foram estudados por diferentes grupos de pesquisa [30][31][32][33][34] sendo as conclusões referentes à miscibilidade contraditórias. Enquanto Martuscelli et al 30,31 observaram apenas uma transição vítrea para as blendas, Lima e Felisberti 32 observaram duas transições vítreas tanto para blendas com poli(epicloridrina) como com o copolímero equimolar poli(epicloridrina-co-óxido de etileno).…”

Crystallization behavior and thermal property of biodegradable poly(3‐hydroxybutyrate)/multi‐walled carbon nanotubes nanocomposite

“…Polymer blending and nanocomposite preparation have often been employed for the wider practical application of PHB, which is often limited by its brittleness and narrow processing window. PHB has been found to be miscible with some polymers such as poly(vinyl acetate) (PVAc), poly(epichlorohydrin) (PECH), poly(vinyl phenol) (PVPh), poly(vinylidene fluoride) (PVDF), poly(vinylidene chloride‐ co ‐acrylonitrile) (PVDCAN), and poly(ethylene oxide) (PEO) 2–7. However, PHB shows immiscibility with poly( ε ‐caprolactone) (PCL), poly(cyclohexyl methacrylate) (PCHMA), poly(hydroxyoctanoate) (PHO), high molecular weight poly(L‐lactide) (PLLA), poly(methylene oxide) (PMO), and poly(butylene succinate) (PBSU) 8–13.…”