Synthesis of thermotropic polybenzoxazole using 3-amino-4-hydroxybenzoic acid

3-Amino-4-hydroxybenzoic acid production from glucose and/or xylose via recombinant Streptomyces lividans

The aromatic compound 3-amino-4-hydroxybenzoic acid (3,4-AHBA) can be employed as a raw material for high-performance industrial plastics. The aim of this study is to produce 3,4-AHBA via a recombinant Streptomyces lividans strain containing griI and griH genes derived from Streptomyces griseus using culture medium with glucose and/or xylose, which are the main components in lignocellulosic biomass. Production of 3,4-AHBA by the recombinant S. lividans strain was successful, and the productivity was affected by the kind of sugar used as an additional carbon source. Metabolic profiles revealed that L aspartate-4-semialdehyde (ASA), a precursor of 3,4-AHBA, and coenzyme NADPH were supplied in greater amounts in xylose medium than in glucose medium. Moreover, cultivation in TSB medium with a mixed sugar (glucose/xylose) was found to be effective for 3,4-AHBA production, and optimal conditions for efficient production were designed by changing the ratio of glucose to xylose. The best productivity of 2.70 g/L was achieved using a sugar mixture of 25 g/L glucose and 25 g/L xylose, which was 1.5 times higher than the result using 50 g/L glucose alone. These results suggest that Streptomyces is a suitable candidate platform for 3,4-AHBA production from lignocellulosic biomass-derived sugars under appropriate culture conditions.

Polyimides containing a novel bisbenzoxazole with high T g and low CTE

A novel diamine named (2,2'-bibenzoxazole)-5,5'-diamine (DBOA) and derived polyimides (PIs) were successfully synthesized. The rigid, linear, symmetrical molecular structure and the strong charge transfer complex (CTC) were considered to be the reasons for the improved molecular packing and enhanced thermal properties of the polymers. These DBOA based PIs exhibited a higher glass transition temperature (T g) and lower coefficient of thermal expansion (CTE) than traditional benzoxazole (BOA) based PIs. Meanwhile, the PI derived from DBOA and BPDA (3,3',4,4'-biphenyltetracarboxylic dianhydride) exhibited high T g (395 °C) and low CTE (8.9 ppm per °C), and is expected to be applied in organic light-emitting diode (OLED) displays.

Dataset of various characterizations for novel bio-based plastic poly(benzoxazole-co-benzimidazole) with ultra-low dielectric constant

The data presented in this specified data article comprise of various characterization such as: structural, thermal, elemental etc. to understand the novel structure and specific properties of the bio-based plastic as described in the main research article "High-performance poly (benzoxazole/benzimidazole)bio-based plastics with ultra-low dielectric constant from 3-amino-4-hydroxybenzoic acid" [1]. The data of 1H NMR spectra of two monomers and their HCl salt formation required for polymerization, FT-IR spectra of polymer formation before and after thermal ring-closing and additionally supported by the thermogravimetric plots where mass loss due to water is observed around 400 °C (thermal ring closing temperature). Solvent plays effective role to change dielectric properties significantly, complete removal of the remaining solvents was confirmed by X-ray photoelectron spectroscopy (XPS) technique. Wide-angle XRD dataset was presented here to make an idea about degree of crystallinity of the prepared polymers.