Although polyurethane (PUR) plastics play important roles in daily life, its wastes bring serious environmental pollutions. Biological (enzymatic) degradation is considered as an environmentally friendly and low-cost method for PUR waste recycling, in which the efficient PUR-degrading strains or enzymes are crucial. In this work, a polyester PUR-degrading strain YX8-1 was isolated from the surface of PUR waste collected from a landfill. Based on colony morphology and micromorphology observation, phylogenetic analysis of 16S rDNA and gyrA gene, as well as genome sequence comparison, strain YX8-1 was identified as Bacillus altitudinis. The results of high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) showed that strain YX8-1 was able to depolymerize self-synthesized polyester PUR oligomer (PBA-PU) to produce a monomeric compound 4, 4'-methylene diphenylamine. Furthermore, strain YX8-1 was able to degrade 32% of the commercialized polyester PUR sponges within 30 days. This study thus provides a strain capable of biodegradation of PUR waste, which may facilitate the mining of related degrading enzymes.
Polyurethanes/chemistry* ; Polyesters/chemistry* ; Chromatography, Liquid ; Phylogeny ; Tandem Mass Spectrometry ; Bacteria/metabolism* ; Biodegradation, Environmental

With the environmental pollution caused by waste plastics becoming increasingly serious, biodegradable polyester has become the focus of public attention. Poly(butylene adipate-co-terephthalate) (PBAT) is a biodegradable polyester formed by the copolymerization of aliphatic and aromatic groups, which has excellent performance of both. The degradation of PBAT under natural conditions requires strict environmental conditions and long degradation cycle. To address these shortcomings, this study explored the application of cutinase in PBAT degradation and the impact of butylene terephthalate (BT) content on the biodegradability of PBAT, so as to improve the degradation rate of PBAT. Five Polyester degrading enzymes from different sources were selected to degrade PBAT to pick out the most efficient enzyme. Subsequently, the degradation rate of PBAT materials with different BT content were determined and compared. The results showed that cutinase ICCG was the best enzyme for PBAT biodegradation, and the higher the BT content, the lower the degradation rate of PBAT. Furthermore, the optimum temperature, buffer type, pH, the ratio of enzyme to substrate (E/S) and substrate concentration in the degradation system were determined to be 75 ℃, Tris HCl, 9.0, 0.4% and 1.0% respectively. These findings may facilitate the application of cutinase in PBAT degradation.
Polyesters/chemistry* ; Adipates

The therapeutic application of deoxypodophyllotoxin (DPT) is limited due to its poor water solubility and stability. In the present study, the micelles assembled by the amphiphilic block copolymers (mPEG-PDLLA) were constructed to improve the solubility and safety of DPT for their in vitro and in vivo application. The central composite design was utilized to develop the optimal formulation composed of 1221.41 mg mPEG-PDLLA, the weight ratio of 1 : 4 (mPEG-PDLLA : DPT), 30 mL hydration volume and the hydration temperature at 40 °C. The results showed that the micelles exhibited uniformly spherical shape with the diameter of 20 nm. The drug-loading and entrapment efficiency of deoxypodophyllotoxin-polymeric micelles (DPT-PM) were about (20 ± 2.84)% and (98 ± 0.79)%, respectively, indicating that the mathematical models predicted well for the results. Compared to the free DPT, the cytotoxicity showed that blank micelles possessed great safety for Hela cells. In addition, the DPT loaded micelle formulation achieved stronger cytotoxicity at the concentration of 1 × 10 mol·L, which showed significant difference from free DPT (P < 0.05). In conclusion, the micelles were highly promising nano-carriers for the anti-tumor therapy with DPT.
Antineoplastic Agents ; chemistry ; toxicity ; Cell Survival ; drug effects ; Drug Carriers ; chemistry ; Drug Delivery Systems ; methods ; Drug Design ; HeLa Cells ; Humans ; Micelles ; Particle Size ; Podophyllotoxin ; analogs & derivatives ; chemistry ; toxicity ; Polyesters ; chemistry ; Polyethylene Glycols ; chemistry ; Solubility ; Surface Properties

Polylactic acid is synthesized indirectly by the polymerization method, according to the standard GB/T 16886.18-2011, the evaluation parameters and methods about chemical characterization of polylactic acid have been established. By using rigorous and comprehensive comparative analysis, the chemical equivalency of domestic and imported polylactic acid materials has been proved, along with the "Medical Device Biology Evaluation and Review Guide", paving the way of using domestic polylactic acid in implantable medical devices.
Equipment and Supplies ; Lactic Acid ; Polyesters ; chemistry ; Polymers

OBJECTIVETo prepare insulin-loaded polymeric nanoparticles based on polyethyleneimine-polycaprolactone- polyethylene glycol-polycaprolactone-polyethyleneimine pentablock copolymers and evaluate its in vitro release of insulin.

METHODSPolycaprolactone-polyethylene glycol-polycaprolactone (PCL-PEG-PCL) triblock copolymer was synthesized by ring-opening polymerization method, and the pentablock copolymer was prepared by Michael addition reaction. The copolymers obtained were characterized by Fourier-transform infrared (FT-IR) spectroscopy and (1)H-NMR and their critical aggregation concentration (CAC) was measured by fluorescence technique with pyrene as the probe. Insulin-loaded polymeric nanoparticles based on the pentablock copolymers were prepared by solvent evaporation method that exploited the cationic nature of PEI-PCL-PEG-PCL-PEI to allow the formation of ionic complexes with anionic biomolecules such as insulin. The prepared nanoparticles were further characterized by Malvern laser particle sizer and transmittion electron microscopy (TEM). The drug loading, encapsulation efficiency and in vitro release profile of the nanoparticles were analyzed using Bradford method.

RESULTSUsing copolymer PEI10K-PCL4K-PEG2K-PCL4K-PEI10K as the drug carrier, the spherical nanoparticles prepared with an optimal insulin-coplymer mass ratio of 40% allowed the maximum insulin loading of (18.63∓0.07)% and had an average particle size of 175.30∓19.51 nm. The prepared nanoparticles was capable of sustained release of insulin for as long as 48 h in vitro, and the burst release could be minimized by incorporation of PEI in the triblock copolymer.

CONCLUSIONThe insulin-loaded polymeric nanoparticles based on the pentablock copolymers allow sustained release of insulin in vitro, and PEI can enhance sustained drug release and reduce burst drug release.

Delayed-Action Preparations ; Drug Carriers ; chemistry ; Drug Liberation ; Insulin ; pharmacokinetics ; Nanoparticles ; chemistry ; Particle Size ; Polyesters ; chemistry ; Polyethylene Glycols ; chemistry ; Polymers ; chemistry ; Spectroscopy, Fourier Transform Infrared

Poly lactic acid (PLA)/Poly (butyleneadipate-co-terephthalate)(PBAT) and glyceryl triacetate (GTA) blend were prepared by torque rheometer, and the effect of GTA on thermodynamical performance, mechanical properties and microstructure of PLA/PBAT composites were studied using differential scanning calorimeter(DSC), dynamic mechanical analysis(DMA), universal testing machine, impact testing machine and scanning electron microscope(SEM). After adding GTA, Tg values of the two phases gradually became closer, blends cold crystallization temperature and melting temperature decreased. When with 3 phr GTA, the dispersed phase particle size of PLA/PBAT blend decreased. Mechanics performance test showed that the elongation at break and impact strength of the PLA/PBAT blend was greatly increased with 3 phr GTA, and the elongation at break increased 2.6 times, improved from 17.7% to 64.1%.
Acetates ; chemistry ; Calorimetry, Differential Scanning ; Crystallization ; Lactic Acid ; Polyesters ; chemistry ; Polymers ; Temperature

A series of bio-based thermosetting polyurethanes (Bio-PUs) were synthesized by the crosslinking reaction of polylactide and its copolymers diols with hexamethylene diisocyanate (HDI) trimer. The obtained Bio-PUs were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Thermal Gravimetric Analysis (TGA), universal tensile testing machine and cytotoxicity test. Results indicate that the PLA copolymer (P(LA-co-CL)) diols reduced the glass transition temperature (Tg) of Bio-PUs and improved their thermal stability, compared with PLA diols. The Bio-PUs synthesized from P (LA-co-CL) diols exhibit better mechanical performance and shape memory properties. Especially, Young modulus and elongation at break of the obtained Bio-PUs were 277.7 MPa and 230% respectively; the shape recovery time of the obtained Bio-PUs at body temperature was only 93 s. Furthermore, alamar blue assay results showed that the obtained Bio-PUs had no cell toxicity.
Biocompatible Materials ; chemistry ; Materials Testing ; Polyesters ; chemistry ; Polymers ; Polyurethanes ; chemistry ; Spectroscopy, Fourier Transform Infrared ; Temperature

Poly (lactic acid) (PLA) is a polymer synthesized from lactic acid with good biocompatibility and biodegradability. At present, PLA manufactured on industrial scale is mainly synthesized from L-lactic acid. The obtained products have good transparency but poor heat resistance. Adding nucleating agents could increase the crystallinity of PLA, to improve heat resistance. We reviewed the progress of research on organic and inorganic nucleating agents that can be used for PLA synthesis.
Chemical Industry ; Lactic Acid ; Polyesters ; chemistry ; Polymers

Poly lactic acid (PLA) fibers a biodegradable fiber produced from PLA resin by melt spinning, solvent spinning or electrostatic spinning. Based on the excellent safety, comfortability, environmental protection and good mechanical properties, PLA can be widely applied in textile fabric, nonwoven, filler fabric and many downstream health products application, such as sanitary napkins, baby diapers, facial masks, and wipes.
Biotechnology ; Chemical Industry ; Lactic Acid ; Polyesters ; chemistry ; Polymers

In this review, we presented the industrial status of biomanufactured polyhydroxyalkanoates (PHA), including poly (3-hydroxybutyrate) (PHB), poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly (3-hydroxybutyrate-co-4-hydroxybutyrate) (P3/4HB)), and poly (3-hydroxybutyrate-3-hydroxycaproate) (PHBH). A lot of modification studies, aimed at solving problems of poor thermal stability, narrow processing window and other drawbacks of PHA, are discussed. The properties of PHA can be optimized by using proper modification method, in order to expand its applications.
3-Hydroxybutyric Acid ; Biotechnology ; Hydroxybutyrates ; Polyesters ; Polyhydroxyalkanoates ; chemistry