UV-photodegradation of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHB-HHx)

Abstract

The effects of ultraviolet (UV) radiation on the properties of the biodegradable polymer, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHB-HHx), were evaluated. Photodegradation was followed by changes in molecular weight, crystallinity, morphology, and thermal properties. PHB-HHx undergoes both chain scission and crosslinking reactions upon UV irradiation. The crystallinity of PHB-HHx was higher during UV-photodegradation. scanning electron microscopy (SEM) micrographs of the PHB-HHx surface before and after UV exposure show that the photodegradation occurred via bulk erosion, not surface erosion. IR spectra showed that both the crystalline and amorphous portions of PHB-HHx were photodegraded through a Norrish type I reaction.

Surface Modification of Polyhydroxyalkanoates toward Enhancing Cell Compatibility and Antibacterial Activity

“…Both the crystalline and amorphous portions of PHBHHx were photodegraded through a Norrish type I reaction. Photodegradation was followed by changes in molecular weight, crystallinity, morphology, and thermal properties . Under inhomogeneous radiation, PHBHHx powder showed significant loss and a broad distribution of molecular weight.…”

“…Photodegradation was followed by changes in molecular weight, crystallinity, morphology, and thermal prop erties. [74] Under inhomogeneous radiation, PHBHHx powder showed significant loss and a broad distribution of mole cular weight. Interestingly, the films made of the UVradiated powder maintained the mechanical properties, however, the PHBHHx films being subjected to direct UV radiation became very brittle, and their degradation was faster than that of the radiated powders.…”

“…Increased wettability, mineralization, attachment, and proliferation of bone marrow stromal cell and chondrocytes [66][67][68][69][70][71][72] PHB, PHBHHx O 2 or air -Increased crystallinity, brittleness, biodegradability, and growth of L929 [74][75][76] Plasma treatment PHBV O 2 plasma Ester, carboxyl, carbonyl Increased hydrophilicity, but maintained only 3-4 months; increased roughness and degradation; increased ALP activity of osteoblasts; increased reattachment of D407 cells [79][80][81][82][83][84] PHBV N 2 plasma CN, CN, CONH Increased hydrophilicity, roughness, and attachment of Vero [85][86][87] PHB, PHBV NH 3 plasma Amino, amide Increased hydrophilicity with a long term stability [88,89] PHBV CO 2 plasma Carbonylic, carboxylic Increased hydrophilicity, roughness, and degradation [90] PHO Air plasma (acrylamide) Amide Increased hydrophilicity [91] PHB, PHBV Allylamine, PEG, and ethylenediamine plasma -Increased cellular resistance; decreased crystal growth [92][93][94] [95] PHB, P3HB4HB Ar plasma (acrylic acid) Carboxylic Increased surface polarity, adhesion, and proliferation of NIH 3T3 cell; decreased biodegradability [96,97] PHB, PHBV Perfluorocarbon plasma CF Decreased surface hydrophilicity and biodegradation [98][99][100] γRadiation graft polymerization is an effective and eco nomical treatment for surface modification. Usually, the grafting percentage depended on differences in regularity in the crystalline regions or crystallinity, and rate of radical decay that corresponded well to radical consumption in graft polym erization.…”

Studies on Chemical IR Images of Poly(hydroxybutyrate–co–hydroxyhexanoate)/Poly(ethylene glycol) Blends and Two-Dimensional Correlation Spectroscopy

“…To improve the properties of PHB, many attempts have been studied by copolymerization [2,8,9,10,11,12] and blending [13,14,15] with the other polymers. The PHB-based copolymers have been extensively studied using infrared (IR) [16,17,18,19] and Raman [8,10,20] spectroscopies, wide-angle X-ray scattering (WAXS) [11,20,21], X-ray diffraction (XRD) [22,23], differential scanning calorimetry (DSC) [24,25], and so on.…”

In vitro cytotoxicity of superheated steam hydrolyzed oligo((R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate) and characteristics of its blend with poly(L-lactic acid) for biomaterial applications

“…Polyhydroxyalkanoates (PHAs) are bacterial polymers produced as intracellular polymeric material through microbial fermentation under unbalanced nutrient conditions. Poly(3-hydroxybutyrate) (PHB), which is the most common representative of PHA family, exhibits a strong configuration of stereo regularity due to isotactic arrangements of pendant groups in its carbon backbone as a result of biologically catalyzed polymerization [ 1 ]. However, the configuration led to brittleness in its mechanical properties.…”