The effect of chain extension method on the properties of polyurethane/SiO2 composites

2012 ◽  
Vol 35 ◽  
pp. 358-362 ◽  
Author(s):  
Zhiping Lv ◽  
Xiaoning Li ◽  
Xiang Yu
Keyword(s):  
Chain Extension ◽  
Extension Method

A chain extension method for apocarotenoids; lycopene and lycophyll syntheses

2015 ◽  
Vol 572 ◽  
pp. 142-150 ◽  
Author(s):  
Jeongae Choi ◽  
Eun-Taek Oh ◽  
Sangho Koo
Keyword(s):  
Chain Extension ◽  
Extension Method ◽  
A Chain

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.

Shear‐sensitive chain extension of dissolved poly(ethylene oxide) by aluminate ions

2020 ◽  
Author(s):  
Satyam Srivastava ◽  
Zachary Fink ◽  
Elizabeth G. Burns ◽  
Thomas P. Russell ◽  
David A. Hoagland
Keyword(s):  
Ethylene Oxide ◽  
Chain Extension ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

scholarly journals Enzymatic Synthesis of Muconic Acid-Based Polymers: Trans, Trans-Dimethyl Muconate and Trans, β-Dimethyl Hydromuconate

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2498
Author(s):  
Dina Maniar ◽  
Csaba Fodor ◽  
Indra Karno Adi ◽  
Albert J. J. Woortman ◽  
Jur van Dijken ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Renewable Resources ◽  
Enzymatic Synthesis ◽  
Enzyme Catalysis ◽  
Unsaturated Polyester ◽  
Chain Extension ◽  
Side Reactions ◽  
Muconic Acid ◽  
Thermal Stabilities ◽  
Polyester Resins

The vast majority of commodity polymers are acquired from petrochemical feedstock, and these resources will plausibly be depleted within the next 100 years. Therefore, the utilization of carbon-neutral renewable resources for the production of polymers is crucial in modern green chemistry. Herein, we report an eco-friendly strategy that uses enzyme catalysis to design biobased unsaturated (co)polyesters from muconic acid derivatives. This method is an attractive pathway for the production of well-defined unsaturated polyesters with minimum side reactions. A suite of characterization techniques was performed to probe the reaction mechanism and properties of the obtained polyesters. It is rationalized that the alkene functionality of the muconate monomers plays an important role in the enzyme catalysis mechanism. The rendered polyesters possessed excellent thermal stabilities and unreacted alkene functionality that can consecutively undergo chain extension, copolymerization, or act as an anchor for other functional groups. These properties open new avenues in the fields of unsaturated polyester resins and photosensitive coatings.

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