Synthesis and characterization of maleated poly(3‐hydroxybutyrate)

Abstract

Graft copolymerization of maleic anhydride (MA) onto poly(3-hydroxybutyrate) (PHB) was carried out by use of benzoyl peroxide as initiator. The effects of various polymerization conditions on graft degree were investigated, including solvents, monomer and initiator concentrations, reaction temperature, and time. The monomer and initiator concentrations played an important role in graft copolymerization, and graft degree could be controlled in the range from 0.2 to 0.85% by changing the reaction conditions. The crystallization behavior and the thermal stability of PHB and maleated PHB were studied by DSC, WAXD, optical microscopy, and TGA. The results showed that, after grafting MA, the crystallization behavior of PHB was obviously changed. The cold crystallization temperature from the glass state increased, the crystallization temperature from the melted state decreased, and the growth rate of spherulite decreased. With the increase in graft degree, the banding texture of spherulites became more distinct and orderly. Moreover, the thermal stability of maleated PHB was obviously improved, compared with that of pure PHB. Its thermal decomposition temperature was enhanced by about 20°C. In addition, the introduction of the MA group promoted the biodegradability of PHB.

Poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)‐based biocomposites reinforced with kenaf fibers

“…In fact, it is well known that reactions between MA groups grafted onto polymeric backbones and hydroxyl groups of cellulose fibers can occur during the mixing, enhancing the compatibilization among composite components. 15,23 A compatibilization strategy based on PHBV modification was preferred to the chemical modification of cellulose fibers that consists on the esterification of the cellulose fraction of the fibers by using dicarboxyl acid anhydrides such as succinic anhydride (SA) and MA. The esterification reaction is illustrated in Scheme 2.…”

Preparation and Characterization of Maleic Anhydride Grafted Poly(Hydroxybutirate-CO-Hydroxyvalerate) – PHBV-g-MA

“…Authors supposed that introducing MA onto PHB chains could disturb the regularity of PHB chains, then control the morphological structures and improve its properties 19 .…”

Synthetic routes to degradable copolymers deriving from the biosynthesized polyhydroxyalkanoates: A mini review

“…Maleic anhydride showed good reactivity and controllability in free-radical polymerization so as to avoid long and undegradable graft chains via homopolymerization. The crystallization temperature of the graft decreased, and the thermal decomposition temperature increased by ~20°C compared with that of PHB homopolymer [128][129][130][131]. The drawback of the benzoyl peroxide-initiated grafting polymerization lies in the high reaction temperature, the large amount of solvents and high energy consumption, and the difficulties in purifying the product.…”