Poly(hydroxybutyrate) and epichlorohydrin elastomers blends: Phase behavior and morphology

Preparation of the Heterogeneous Saponified Poly(Vinyl Alcohol)/Poly(Methyl Methacrylate-Methallyl Alcohol) Blend Film

For the first time, poly(vinyl alcohol) (PVA)/poly(methyl methacrylate-methallyl alcohol) (P(MMA-MAA)) (9:1, 7:3, 5:5) blend films were made simultaneously using the saponification method in a heterogeneous medium from poly(vinyl acetate) (PVAc)/poly(methyl methacrylate) (PMMA) (9:1, 7:3, 5:5) blend films, respectively. The surface morphology and characteristics of the films were investigated using optical microscopy (OM), atomic force microscopy (AFM), X-ray diffractometer (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Moreover, the effect of the PVAc content on the degree of saponification (DS) of the PVAc/PMMA films were evaluated and revealed that the obtained DS value increased with the increase in PVAc content in the PVAc/PMMA blend films. According to the OM results, the saponified films demonstrated increased surface roughness compared with the unsaponified films. The AFM images revealed morphological variation among the saponified PVAc/PMMA blend films with different mass ratios of 9:1, 7:3, and 5:5. According to the DSC and TGA results, all blend film types exhibited higher thermal property after the saponification treatment. The XRD and FTIR results confirmed the conversion of the PVAc/PMMA into PVA/P(MMA-MAA) films. Thus, our present work may give a new idea for making blend film as promising medical material with significant surface properties based on hydrophilic/hydrophobic strategy.

A Critical Review of the Performance and Soil Biodegradability Profiles of Biobased Natural and Chemically Synthesized Polymers in Industrial Applications

This review explores biobased polymers for industrial applications, their end fate, and most importantly, origin and key aspects enabling soil biodegradation. The physicochemical properties of biobased synthetic and natural polymers and the primary factors governing degradation are explored. Current and future biobased systems and factors allowing for equivalent comparisons of degradation and possible sources for engineering improved biodegradation are reviewed. Factors impacting ultraviolet (UV) stability of biopolymers have been described including methods to enhance photoresistance and impact on biodegradation. It discusses end-fate of biopolymers in soil and impact of residues on soil health. A limited number of studies examine side effects (e.g., microbial toxicity) from soil biodegradation of composites and biopolymers. Currently available standards for biodegradation and composting have been described with limitations and scope for improvements. Finally, design considerations and implications for sustainable polymers used, under consideration, and to be considered within the context of a rational biodegradable strategy are elaborated.

Toughening Biosourced Poly(lactic acid) and Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) Blends by a Renewable Poly(epichlorohydrin-co-ethylene oxide) Elastomer

A series of sustainable polymer blends from renewable poly(lactic acid) (PLA), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P_3,4HB), and poly(epichlorohydrin-co-ethylene oxide) (ECO) elastomer were fabricated via a melt blending method to gain balanced physical performance. The interplay of the composition, mutual miscibility, and viscosity ratio of the pristine PLA, P_3,4HB, and ECO elastomer resulted in diverse phase structures of the ternary blends. An excellent flexibility at an elongation of 270% was achieved for the PLA/P_3,4HB/ECO (70/20/10) blend with a core-shell structure. The PLA/P_3,4HB/ECO (70/10/20) blend with a phase-separated structure exhibited a high impact strength of 54 KJ/m², which is 25 times over that of the neat PLA. The relationship between the phase structure and physical performance of the blend was analyzed based on the compositions, surface tension, and physical characteristics of the neat components. Combining the compatibilization of the P_3,4HB phase and ECO elastomer toughening played a crucial role in enhancing the mechanical properties of the blends.

Blends of poly(3-hydroxybutyrate) and poly(p-dioxanone): miscibility, thermal stability and biocompatibility

The miscibility, the thermal degradation and biocompatibility of the blends of two biodegradable and bioreabsorbable polymers, brittle polyhydroxybutyric acid (PHB) and flexible poly (p-dioxanone) (PPD) are reported. The blends were prepared by casting from chloroform solutions and analyzed by differential scanning calorimetry, dynamic mechanical analysis, scanning electron microscopy and thermal gravimetric analysis. The blends are immiscible and present promising morphology of a dense phase and a microporous phase, one or the other being the matrix, depending on the composition. Despite the immiscibility, the thermal stability under an inert atmosphere is improved for both polymers. The results obtained from toxicity tests showed that PHB/PPD blends do not present indirect or direct cytotoxicity as a substrate for cellular growth.