scholarly journals Crystallization and Alkaline Degradation Behaviors of Poly(l-Lactide)/4-Armed Poly(ε-Caprolactone)-Block-Poly(d-Lactide) Blends with Different Poly(d-Lactide) Block Lengths

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2195
Author(s):  
Suyang Dai ◽  
Min Wang ◽  
Zhuoxin Zhuang ◽  
Zhenbo Ning
Keyword(s):  
Isothermal Crystallization ◽  
Ring Opening ◽  
Degradation Rate ◽  
Crystallization Rate ◽  
Ring Opening Polymerization ◽  
Alkaline Degradation ◽  
Blend Films ◽  
Neat Plla ◽  
Close Relationship ◽  
Degradation Behaviors

Four-armed poly(ε-caprolactone)-block-poly(d-lactide) (4-C-D) copolymers with different poly(d-lactide) (PDLA) block lengths (Mn,PDLAs) were synthesized by sequential ring-opening polymerization (ROP). The formation of stereocomplex (SC) crystallites in the 80/20 poly(l-lactide) (PLLA)/4-C-D blends were investigated with the change of Mn,PDLA from 0.5 to 1.5 kg/mol. It was found that the crystallization and alkaline degradation of the blends were profoundly affected by the formed SC crystallites. The PLLA/4-C-D0.5 blend had the lowest crystallization rate of the three blends, and it was difficult to see spherulites in this blend by polarized optical microscopy (POM) observation after isothermal crystallization at 140 °C for 4 h. Meanwhile, when Mn,PDLA was 1 kg/mol or 1.5 kg/mol, SC crystallites could be formed in the PLLA/4-C-D blend and acted as nucleators for the crystallization of PLLA homo-crystals. However, the overall crystallization rates of the two blends were still lower than that of the neat PLLA. In the PLLA/4-C-D1.5 blend, the Raman results showed that small isolated SC spherulites were trapped inside the big PLLA homo-spherulites during isothermal crystallization. The degradation rate of the PLLA/4-C-D blend decreased when Mn,PDLA increased from 0.5 to 1.5 kg/mol, and the degradation morphologies had a close relationship with the crystallization state of the blends. This work revealed the gradual formation of SC crystallites with the increase in Mn,PDLA in the PLLA/4-C-D blends and its significant effect on the crystallization and degradation behaviors of the blend films.

Mechanical and biodegradable properties of l-lactide-grafted sisal fiber reinforced polylactide composites

2014 ◽  
Vol 33 (22) ◽  
pp. 2034-2045 ◽  
Author(s):  
Wuchang Fu ◽  
Xiaoqiang Xu ◽  
Hongwu Wu
Keyword(s):  
Ring Opening ◽  
Interfacial Adhesion ◽  
Degradation Rate ◽  
Ring Opening Polymerization ◽  
Sisal Fiber ◽  
Flexural Properties ◽  
Dramatic Improvement ◽  
Polymerization Degree ◽  
Cellulose Fibrils ◽  
Biodegradable Properties

Sisal fiber (SF) was grafted with low polymerization degree polylactide (PLA) according to the principle of coordinative ring-opening polymerization of lactide, and then the lactide-grafted sisal fiber (SF-g-LA) was mixed with PLA to make PLA/SF-g-LA composites. The mechanical properties, morphology, and biodegradability of PLA/SF-g-LA composites were systematically investigated, comparing with untreated SF reinforced PLA (PLA/USF) and alkali-treated SF reinforced PLA (PLA/ASF) composites. Results showed that the interfacial properties between SF-g-LA and PLA matrix showed dramatic improvement. The PLA/SF-g-LA composites exhibited noticeably superior tensile and flexural properties; however, their impact strength decreased slightly compared with pure PLA. All of the composites were buried in soil and different degrees of degradation were achieved. Because of better interfacial adhesion between SF-g-LA and PLA matrix, the degradation rate of PLA/SF-g-LA composite was lower than those of PLA/USF and PLA/ASF composites, although still higher than that of pure PLA. The biodegradation of PLA/SF-g-LA composites was marked by appearance of cavities, the exfoliation of fragmental materials, and the degradation of cellulose fibrils.

scholarly journals PDMAEMA/Polyester Miktopolymers: Synthesis via In-Out Approach, Physicochemical Characterization and Enzymatic Degradation

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1277
Author(s):  
Maria Kupczak ◽  
Anna Mielańczyk ◽  
Dorota Neugebauer
Keyword(s):  
Molecular Weight ◽  
Ring Opening ◽  
Drug Delivery Systems ◽  
Enzymatic Degradation ◽  
Degradation Rate ◽  
Physicochemical Characterization ◽  
Ring Opening Polymerization ◽  
Resonance Spectroscopy ◽  
Hydroxyl Groups ◽  
Pseudomonas Cepacia

Synthesis, physicochemical characterization, and the enzymatic degradation of the amphiphilic miktoarm star-shaped polymers is reported herein. First, star-shaped macroinitiators, based on N,N′-dimethylaminoethyl methacrylate (DMAEMA) and glycerol dimethacrylate (GDMA) ((PDMAEMA)n-PGDMA), were synthesized. Due to the presence of hydroxyl groups in the macroinitiator core, polyesters such as poly(ɛ-caprolactone) (P(ɛ-CL)), polylactide (PLA) and poly(lactide-co-glycolide) (PLGA) were synthesized using ring opening polymerization (ROP). Comprehensive degradation studies on enzymatic degradation, using a lipase from Pseudomonas cepacia, were performed. Enzymatic degradation was monitored by weight measurements and nuclear magnetic resonance spectroscopy (1H NMR). The fastest degradation rate was observed for the polymer with the lowest molecular weight. Amphiphilic miktopolymers may find application as biomaterials for long- or mid-term period drug-delivery systems.

A Recommender System for Inverse Design of Polycarbonates and Polyesters

2020 ◽  
Author(s):  
Nathaniel Park ◽  
Dmitry Yu. Zubarev ◽  
James L. Hedrick ◽  
Vivien Kiyek ◽  
Christiaan Corbet ◽  
...  
Keyword(s):  
Ring Opening ◽  
High Performance ◽  
Recommendation System ◽  
Polymeric Materials ◽  
Monomer Conversion ◽  
Design Strategy ◽  
Ring Opening Polymerization ◽  
Inverse Design ◽  
False Negatives ◽  
Accelerate Development

The convergence of artificial intelligence and machine learning with material science holds significant promise to rapidly accelerate development timelines of new high-performance polymeric materials. Within this context, we report an inverse design strategy for polycarbonate and polyester discovery based on a recommendation system that proposes polymerization experiments that are likely to produce materials with targeted properties. Following recommendations of the system driven by the historical ring-opening polymerization results, we carried out experiments targeting specific ranges of monomer conversion and dispersity of the polymers obtained from cyclic lactones and carbonates. The results of the experiments were in close agreement with the recommendation targets with few false negatives or positives obtained for each class.<br>

Bisurea and Bisthiourea H-Bonding Organocatalysts for Ring-Opening Polymerization: Cues for the Catalyst Design

2019 ◽  
Vol 52 (23) ◽  
pp. 9232-9237 ◽  
Author(s):  
Rukshika S. Hewawasam ◽  
U. L. D. Inush Kalana ◽  
Nayanthara U. Dharmaratne ◽  
Thomas J. Wright ◽  
Timothy J. Bannin ◽  
...  
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Catalyst Design

scholarly journals Controlled Ring-Opening Polymerization of O-Carboxyanhydrides to Synthesize Functionalized Poly(α-Hydroxy Acids)

2021 ◽  
Vol 03 (01) ◽  
pp. 041-050
Author(s):  
Xiaoqian Wang ◽  
Ai Lin Chin ◽  
Rong Tong
Keyword(s):  
Biomedical Engineering ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Metal Catalyst ◽  
Hydroxy Acids ◽  
Controlled Polymerization ◽  
Biodegradable Polyesters ◽  
Recent Advances

Poly(α-hydroxy acids), as a family of biodegradable polyesters, are valuable materials due to their broad applications in packaging, agriculture, and biomedical engineering. Herein we highlight and explore recent advances of catalysts in controlled ring-opening polymerization of O-carboxyanhydrides towards functionalized poly(α-hydroxy acids), especially metal catalyst-mediated controlled polymerization. Limitations of current polymerization strategies of O-carboxyanhydrides are discussed.

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