scholarly journals Cutinase-Like Enzyme from the Yeast Cryptococcus sp. Strain S-2 Hydrolyzes Polylactic Acid and Other Biodegradable Plastics

2005 ◽  
Vol 71 (11) ◽  
pp. 7548-7550 ◽  
Author(s):  
Kazuo Masaki ◽  
Numbi Ramudu Kamini ◽  
Hiroko Ikeda ◽  
Haruyuki Iefuji
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Polylactic Acid ◽  
Biodegradable Plastics ◽  
Remote Homology ◽  
High Molecular Weight Compound ◽  
Polybutylene Succinate

ABSTRACT A purified lipase from the yeast Cryptococcus sp. strain S-2 exhibited remote homology to proteins belonging to the cutinase family rather than to lipases. This enzyme could effectively degrade the high-molecular-weight compound polylactic acid, as well as other biodegradable plastics, including polybutylene succinate, poly (ε-caprolactone), and poly(3-hydroxybutyrate).

scholarly journals Biodegradation of high molecular weight polylactic acid

2012 ◽  
Author(s):  
Petr Stloukal ◽  
Marek Koutny ◽  
Vladimir Sedlarik ◽  
Pavel Kucharczyk
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Polylactic Acid

SOME FACTORS AFFECTING THE KÖNIGS–KNORR SYNTHESIS OF GLYCOSIDES

1961 ◽  
Vol 39 (10) ◽  
pp. 2025-2034 ◽  
Author(s):  
H. R. Goldschmid ◽  
A. S. Perlin
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Silver Oxide ◽  
Condensation Reaction ◽  
Side Reaction ◽  
Ortho Ester ◽  
Factors Affecting ◽  
High Molecular Weight Compound ◽  
Elemental Iodine

Glycosyl halides decompose readily in the presence of silver oxide under conditions generally used for the Königs–Knorr synthesis of glycosides. This "side reaction" probably accounts for the low yields commonly obtained in the synthesis of oligosaccharides, particularly those involving the formation of a glycosidic union through an unreactive secondary position. The rate of the side reaction, as well as that of the normal condensation reaction, is dependent on the condition of the silver oxide, and is retarded markedly by elemental iodine. This latter effect appears to be related to the improved yield obtained in Königs–Knorr syntheses when iodine is used. Among the products formed in the decomposition of 2,3,4,6-tetra-O-acetyl-α-D-mannopyranosyl bromide are 2,3,4,6-tetra-O-acetyl-D-mannose, a heptaacetyl 1,2,1′-linked dimeric orthoacetate, and a second high-molecular-weight compound that also shows ortho ester properties.

scholarly journals High Molecular Weight Poly(lactic acid) Synthesized with Apposite Catalytic Combination and Longer time

2018 ◽  
Vol 34 (4) ◽  
pp. 1984-1990
Author(s):  
Sanjay Kumar Singh ◽  
Prashant Anthony ◽  
Abhishek Chowdhury
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Polylactic Acid ◽  
Renewable Resources ◽  
Sulfonic Acid ◽  
Polymeric Materials ◽  
Poly Lactic Acid ◽  
Direct Polycondensation ◽  
Toluene Sulfonic Acid ◽  
Binary Catalyst

Biodegradable polymeric materials derived from renewable resources have attracted tremendous attention in different application. Polylactic acid (PLA) is one of the most useful biodegradable polymers. It is difficult to synthesize high molecular weight polylactic acid by direct polycondensation. The present work describes the synthesis of high molecular weight PLA by varying the duration of reaction and changing the sequence of catalyst addition. Binary catalyst used was SnCl2.2H2O/maleic anhydride and p-toluene sulfonic acid. PLA with molecular weight (6.503X105) was obtained in 50 hours. FTIR, H1 and 13C NMR ascertained the structure of synthesized PLA whereas GPC was used for determining molecular weight.

scholarly journals High molecular weight of polylactic acid (PLA): A Review on the effect of initiator

2021 ◽  
Vol 4 (1) ◽  
pp. 15
Author(s):  
Norliza Ibrahim ◽  
Anis Nuranisya Shamsuddin
Keyword(s):  
Molecular Weight ◽  
Carboxylic Acid ◽  
High Molecular Weight ◽  
Polylactic Acid ◽  
Ring Opening ◽  
Functional Group ◽  
Nitrogen Atmosphere ◽  
The Other ◽  
Hydroxyl Group ◽  
Aliphatic Polyester

This article reviews various initiator used to synthesize high molecular weight (MW >10,000 g/mol) of polylactic acid (PLA) through ring-opening polymerisation (ROP) of lactide. ROP has been chosen as the best method in producing PLA. On the other hand, stannous octoate (Sn(Oct)2) has been reported as the best catalyst used for ROP method. Many researchers have studied that polymerisation rate with the presence of only Sn(Oct)2 as catalyst is slow compared to polymerisation of lactide with the presence of initiator. An initiator is also favourable in producing high molecular weight of PLA as it can initiate the synthesis of PLA. Therefore, this review focus on ROP method catalysed by Sn(Oct)2 using different solvent as initiator. Among groups of initiators being reviewed are hydroxyl, carboxylic acid, aldehyde, aliphatic polyester and organophosphorus compound. Most of the studies applied in nitrogen atmosphere with a temperature range of 125 to 200 °C, while only one study in vacuum condition. Duration of the polymerisation time is between 1 to 24 hours. Based on the review, alcohol (hydroxyl group initiator) has been reported as the best initiator to produce high molecular weight of PLA. This functional group act as co-initiator molecule that reacts with Sn(Oct)2, forming the initiating stannous alkoxide linkage. The linkage is necessary to propagate monomer addition and hence increase the MW. 

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