The effect of additives interaction on the miscibility and crystal structure of two immiscible biodegradable polymers

Abstract

Poly lactic acid (PLLA) is a promising biopolymer, obtained from polymerization of lactic acid that is derived from renewable resources through fermentation. The characteristic brittleness of PLLA is attributed to slow crystallization rates, which results in the formation of the large spherulites. Its glass temperature is relative high, above room temperature and close to 60 °C, and therefore its applications are limited. The additives poly((R)-3-hydroxybutyrate) (PHB), poly(vinyl acetate) (PVAc) and tributyl citrate (TBC) were used as compatibilizers in the biodegradable polymer blend of (PLLA/PPC). Results from DSC and POM analysis indicated that the blends of PLLA and PPC are immiscible. However, the blends with additives are miscible. TBC as plasticizer was added to PLLA to reduce its Tg. PVAc was used as compatibilizer to improve the miscibility between PLLA and PPC. FT-IR showed about 7 cm -1 shift in the C=O peak in miscible blends due to physical interactions. POM experiments together with the results of DSC and WAXD showed that PHB enhances the crystallization behavior of PLLA by acting as bio nuclei and the crystallization process can occur more quickly. Consequently an increase was observed in the peak intensity in WAXD.

Blending PPO‐based molecules with Pebax MH 1657 in membranes for gas separation

“…The melting temperatures reported in Table show only little variation for the polyether microphase and remain essentially constant for the polyamide phase. Such behavior usually demonstrates immiscibility and can be related to the previous section where a thermodynamic preference toward the polyether phase was predicted, however, with a relatively low affinity based on the interfacial tension. The results show that the applied additives do not act as plasticizers nor spacers on the crystalline domains inside the block copolymer.…”

Blends of ethylene-co-vinyl acetate and poly(3-hydroxybutyrate) with adhesion property

“…Furthermore, the two melting peaks of pure PHB shift to higher temperatures in all blends (from 131 to 138-156°C and from 147 to 154-167°C), this indicating better miscibility which can be favoured by the reduction in molecular mass of PHB during melting. The increase is less important in the blends containing 40 wt% or less PHB (EVA/PHB (70:30) is an exception); furthermore, the melting temperatures of the blends containing more than 50 wt% PHB are very similar ( [29] proposed the existence of physical crosslinking between PHB and different polymers (PLA, polypropylene carbonate -PPC -, polyvinyl acetate -PVAc), and the existence of interactions between the carbonyl (C=O) and methyl (CH 3 ) groups between PHB and PLA, and between PHB and PVAc in polymer blends have been supported in several studies [30][31][32][33][34][35][36]. The crystallinity of EVA, PHB and EVA/PHB blends was determined by X-ray diffraction.…”

“…The existence of physical interactions between EVA and PHB phases in EVA/PHB blends is evidenced by changes in compatibility, crystallinity and viscoelastic properties. The interactions between EVA or PVAc and PHB or PLA or PPC in polymer blends have been ascribed to the disruption of the interactions between the carbonyl (C=O) and methyl (CH 3 ) groups by weak physical interactions with C=O and CH 3 groups of PVAc [28][29][30][31][32][33][34][35][36]. Because of CH 3 and C=O groups also exists in the vinyl acetate domains in EVA, weak interfacial interactions between C=O and CH 3 groups of PHB and CH 3 and C=O groups of EVA can be produced.…”

Modulating matrix‐multicellular response using polysucrose‐blended with poly‐L‐lactide or polydioxanone in electrospun scaffolds for skin tissue regeneration

“…The introduction of amorphous PSuc to PLLA and PDX altered their mechanical properties, displaying an erratic trend in the maximum tensile stress, and Young's modulus at different PSuc concentration attributed to heterogeneous distribution of PSuc across the electrospun mats. Furthermore, a constant decrease in the tensile strain to failure was observed for both PLLA and PDX blends (except for PDX-PSuc 50-50) which can be explained by macrophase separation and poor inter-phase adhesion at which fracture is likely to occur 20,21 . Hence, the results demonstrated the possibility of tailoring the mechanical properties of both PSuc and PLLA or PDX for their applications in tissue regeneration by blending.…”