In situ compatibilization of maleated thermoplastic starch/polyester melt‐blends by reactive extrusion

Abstract

This article concerns the utilization of maleated thermoplastic starch (MTPS) in the reactive extrusion meltblending with poly(butylene adipate-co-terephthalate) (PBAT) in blown film applications. First, MTPS was prepared from cornstarch with glycerol (plasticizer) and maleic anhydride (MA; esterification agent). MTPS was then melt-blended with PBAT in a subsequent downstream extrusion operation. The effects of both polyester and MA contents were studied on the physicochemical parameters of melt-blends. For high polyester fractions (>60 wt%), PBAT-g-MTPS graft copolymers were obtained through transesterification reactions. They were promoted by the MA-derived acidic moieties grafted onto the starch backbone as shown by selective Soxhlet extraction experiments and FTIR analyses. At lower polyester content, no significant reaction occurred more likely due to an inversion in the phase morphology between both components. Tensile properties of PBATg-MTPS graft copolymer containing 70 wt% polyester were much higher as the TPS/PBAT melt-blend modified with MA. This can be explained by a finer morphology of the dispersed phase in the continuous PBAT matrix, and an increased interfacial area for the grafting reaction as attested by morphological studies.

PBAT/TPS Composite Films Reinforced with Starch Nanoparticles Produced by Ultrasound

“…All the X-ray diffraction patterns showed peaks at 2 = 17.5 ∘ , 20.5 ∘ , and 23.2 ∘ , attributed mainly to PBAT [36,37].…”

“…The addition of starch to the PBAT matrix increased the crystallinity, suggesting amylose recrystallization during the extrusion process [38]. The crystallinity associated with the recrystallization of the amylose which occurs may be because during the extrusion process an amylose (amorphous portion of the native starch) can be crystallized and this structural change can increase the degree of crystallinity [36][37][38].…”

Morphology, thermal properties and crystallization kinetics of ternary blends of the polylactide and starch biopolymers and nanoclay: The role of nanoclay hydrophobicity

“…Starch is the most abundant [3] inexpensive biopolymer, but attempts to incorporate it into PLA have been challenging due to its granularity and the hydrophilic nature conferred by hydroxyl-groups on the glucose backbone [4]. PLA-starch compatibility has been increased by hydrophobic modification of starch [5] and by using cross-linkers and/or a compatibilizers such as maleic anhydride [6][7][8]. However, even with such modifications, the amount of starch added to the blend cannot exceed approximately 20 wt% without adversely affecting the properties of PLA [5].…”

Solvent-free preparation, characterization, and properties of SEBS–g–polycarbonate copolymers

“…[32,33] A third attractive strategy, by a continuous process, consists to synthesize, in situ, a block or graft copolymer at the interface between the immiscible polymers. [24,[34][35][36][37][38][39][40][41][42][43][44][45][46] Reactive extrusion can then be used with the advantage to combine simultaneously both the blending and the chemical reaction with short residence times. These reactions often happen between two functional groups located at the end of the polymer chains.…”