Synthesis of high-molecular-weight aliphatic-aromatic copolyesters from poly(ethylene-co -1,6-hexene terephthalate) and poly(L -lactic acid) by chain extension

2009 ◽  
Vol 47 (21) ◽  
pp. 5898-5907 ◽  
Author(s):  
Wen-Da Li ◽  
Jian-Bing Zeng ◽  
Yi-Dong Li ◽  
Xiu-Li Wang ◽  
Yu-Zhong Wang
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
High Molecular Weight ◽  
Chain Extension ◽  
Poly Ethylene

Non-toxic polyester urethanes based on poly(lactic acid), poly(ethylene glycol) and lysine diisocyanate

2016 ◽  
Vol 32 (3) ◽  
pp. 225-241 ◽  
Author(s):  
Alena Pavelková ◽  
Pavel Kucharczyk ◽  
Zdenka Kuceková ◽  
Jiří Zedník ◽  
Vladimír Sedlařík
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Ethylene Glycol ◽  
Biomedical Applications ◽  
Hydrolytic Degradation ◽  
Chain Extension ◽  
Poly Lactic Acid ◽  
Side Reactions ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene

Poly(lactic acid)-based polymers are highly suitable for temporary biomedical applications, such as tissue support or drug delivery systems. Copolymers of different molecular weight based on poly(lactic acid) and poly(ethylene glycol) were prepared by polycondensation, catalysed by hydrochloric acid. A chain-extension reaction with l-lysine ethyl ester diisocyanate was employed afterwards to obtain polyester urethanes with enhanced properties. The GPC results showed that the molecular weights of the products reached about 50,000 g·mol−1 and the hydrolytic progress was rapid in the first 2 weeks; the drop in Mn equalled approximately 70%. Additionally, elemental analysis of the buffer medium proved that hydrolytic degradation was more rapid in the first stage. Tensile-strength testing revealed that ductility increased alongside reduced molecular weight of poly(ethylene glycol), also suggesting that polymer branching occurred due to side reactions of isocyanate. Based on the envisaged biomedical applications for these polymers, cytotoxicity tests were carried out and the cytotoxic effect was only moderate in the case of 100% polymer extract prepared according to ISO standard 10993-12. In their research, the authors focused on preparing metal-free, catalysed synthesis of polyester urethanes, which could prove useful to numerous biomedical applications.

scholarly journals Poly(lactic Acid): A Versatile Biobased Polymer for the Future with Multifunctional Properties—From Monomer Synthesis, Polymerization Techniques and Molecular Weight Increase to PLA Applications

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1822
Author(s):  
Evangelia Balla ◽  
Vasileios Daniilidis ◽  
Georgia Karlioti ◽  
Theocharis Kalamas ◽  
Myrika Stefanidou ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Chain Extension ◽  
Poly Lactic Acid ◽  
Plastic Pollution ◽  
Practical Applications ◽  
Decomposition Reactions ◽  
Melt Polycondensation ◽  
Polymerization Conditions ◽  
Molecular Weight Increase

Environmental problems, such as global warming and plastic pollution have forced researchers to investigate alternatives for conventional plastics. Poly(lactic acid) (PLA), one of the well-known eco-friendly biodegradables and biobased polyesters, has been studied extensively and is considered to be a promising substitute to petroleum-based polymers. This review gives an inclusive overview of the current research of lactic acid and lactide dimer techniques along with the production of PLA from its monomers. Melt polycondensation as well as ring opening polymerization techniques are discussed, and the effect of various catalysts and polymerization conditions is thoroughly presented. Reaction mechanisms are also reviewed. However, due to the competitive decomposition reactions, in the most cases low or medium molecular weight (MW) of PLA, not exceeding 20,000–50,000 g/mol, are prepared. For this reason, additional procedures such as solid state polycondensation (SSP) and chain extension (CE) reaching MW ranging from 80,000 up to 250,000 g/mol are extensively investigated here. Lastly, numerous practical applications of PLA in various fields of industry, technical challenges and limitations of PLA use as well as its future perspectives are also reported in this review.

Hydrolytically and Reductively Degradable High-Molecular-Weight Poly(ethylene glycol)s

2007 ◽  
Vol 208 (24) ◽  
pp. 2642-2653 ◽  
Author(s):  
Alena Braunová ◽  
Michal Pechar ◽  
Richard Laga ◽  
Karel Ulbrich
Keyword(s):  
Molecular Weight ◽  
Ethylene Glycol ◽  
High Molecular Weight ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene ◽  
High Molecular Weight Poly

scholarly journals Synthesis of polylactic acid-diol (PLA-diol) from lactic acid and 1,4-butanediol

2016 ◽  
Vol 19 (4) ◽  
pp. 58-65
Author(s):  
Ha Thi Thai La
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Polyethylene Glycol ◽  
1H Nmr ◽  
Biodegradable Polymer ◽  
Average Molecular Weight ◽  
Chain Extension ◽  
Structure And Properties ◽  
Chain Reaction ◽  
A Chain

In this research, the PLA-diol were synthesized from lactic acid (LA) and 1.4 butanediols (BD) with a tin octoate Sn(Oct)2 catalyst at a temperature of 180 °C and the pressure 5 mmHg. The structure and properties of PLA-diol are analyzed by the following methods: GPC, 1H-NMR and DSC. As a result, with the change in the content of Sn (Oct)2 from 0.1 to 1.0%, the molecular weight Mn of PLA - diol increased gradually from 4.119,2 to 7.359,6 g / mol . In addition, the BD content increased from 2.0% to 5.0%, the average molecular weight of the product decreased gradually from 7.536,9 g / mol to 4.735 g / mol, respectively. This change will affect the ability to use PLA-diol in the next denaturation research to apply in the field of biodegradable polymer such as copolymer with polyurethane, copolymer with polyethylene glycol diacid, or chain extension with other polymer in a chain reaction,...

Stereocomplex electrospun fibers from high molecular weight of poly(L-lactic acid) and poly(D-lactic acid)

2020 ◽  
Vol 40 (2) ◽  
pp. 136-142 ◽  
Author(s):  
Homa Maleki ◽  
Hossein Barani
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Thermal Properties ◽  
High Molecular Weight ◽  
Chemical Properties ◽  
Electrospun Fibers ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Electrospinning Method

AbstractThe stereocomplex formation is a promising method to improve the properties of poly(lactide) (PLA)-based products due to the strong interaction of the side-by-side arrangement of the molecular chains. Recently, electrospinning method has been applied to prepare PLA stereocomplex, which is more convenient. The objective of the current study is to make stereocomplexed PLA nanofibers using electrospinning method and compare their properties and structures with pure poly(l-lactide) (PLLA) fibers. The stereocomplexed fibers were electrospun from a blend solution of high molecular weight PLLA and poly(d-lactide) (1:1 ratio). The morphology of the obtained electrospun fibers was examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Differential scanning calorimetry was applied to study their thermal properties and crystallinity. Fourier transform infrared spectroscopy (FTIR) test was conducted on the samples to characterize their chemical properties. The SEM and AFM images indicated that smooth uniform fibers with a cylindrical structure were produced. Besides, the FTIR results and thermal properties confirmed that only stereocomplex crystallites formed in the resulting fibers via the electrospinning method.

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