Crystallization behavior and morphology of double crystalline poly(butylene succinate)-poly(ethylene glycol) multiblock copolymers

Non-Isothermal Crystallization Kinetics of Poly(ethylene glycol) and Poly(ethylene glycol)-B-Poly(ε-caprolactone) by Flash DSC Analysis

The non-isothermal crystallization behaviors of poly (ethylene glycol) (PEG) and poly (ethylene glycol)-b-poly(ε-caprolactone) (PEG-PCL) were investigated through a commercially available chip-calorimeter Flash DSC2+. The non-isothermal crystallization data under different cooling rates were analyzed by the Ozawa model, modified Avrami model, and Mo model. The results of the non-isothermal crystallization showed that the PCL block crystallized first, followed by the crystallization of the PEG block when the cooling rate was 50-200 K/s. However, only the PEG block can crystallize when the cooling rate is 300-600 K/s. The crystallization of PEG-PCL is completely inhibited when the cooling rate is 1000 K/s. The modified Avrami and Ozawa models were found to describe the non-isothermal crystallization processes well. The growth methods of PEG and PEG-PCL are both three-dimensional spherulitic growth. The Mo model shows that the crystallization rate of PEG is greater than that of PEG-PCL.

Poly(butylene succinate-co-salicylic acid) copolymers and their effect on promoting plant growth

Biodegradable random copolymers were successfully synthesized by melt polycondensation of poly(butylene succinate) (PBS) and salicylic acid (SA). The obtained copolymers were characterized by proton nuclear magnetic resonance spectroscopy. The effect of different SA contents on the properties of copolymers was investigated by universal testing machine, thermogravimetric analyser, differential scanning calorimetry and X-ray diffraction analysis. The results showed that the copolymers with 0.5% SA contents exhibited excellent elastic modulus (1413.0 MPa) and tensile strength (192.8 MPa), and similar thermal decomposition temperature (≈320°C) compared with pure PBS. By molecular docking simulations, it was proved that the degradability of copolymers was more effective than that of pure PBS with a binding energy of -5.77 kcal mol^-1. PBS copolymers with a small amount of SA were not only biodegradable but could stimulate the growth of green vegetables. So biodegradable copolymers can be used over a wide range as they are environmentally friendly.

New poly(ester-amide) copolymers modified with polyether (PEAE) for anticancer drug encapsulation

New poly(ester-amide) copolymers modified with polyethers were developed for carboplatin encapsulation. These new copolymers contain hydrophobic blocks made of tyrosine derivative and dimer fatty acid, and poly(ethylene glycol) (PEG) as hydrophilic blocks. Short-term hydrolytic degradation revealed high water absorption, slight increase of pH of simulated body fluid and change of sample shape, which indicated the erosive mechanism of polymers degradation. Poly(ester-amide)-PEG copolymers were used for microspheres preparation and carboplatin encapsulation. A double emulsification process was used to produce microspheres with an average diameter of 20-30 μm. It was found that the amount of drug released was controlled by the molecular mass of PEG used for microspheres preparation. Mathematical models were used to elucidate the release mechanism of the carboplatin from the microspheres. The results demonstrate that poly(ester-amide)-PEG copolymers may be used for targeted carboplatin encapsulation and release.

Improving crystallization and processability of PBS via slight cross-linking

PBS containing a cross-linkable comonomer containing an alkynyl group can slightly cross-link during the preparation, which makes PBS show a fast crystallization rate and high melt viscosity.

Structures and morphologies of biocompatible and biodegradable block copolymers

Biocompatible and biodegradable block copolymers (BBCPs) have become increasingly important in polymer science, and have many potential applications in polymer materials.