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,...

scholarly journals Preparation of Higher Molecular Weight Poly (L-lactic Acid) by Chain Extension

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Chenguang Liu ◽  
Yuliang Jia ◽  
Aihua He
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Average Molecular Weight ◽  
Hexamethylene Diisocyanate ◽  
Chain Extension ◽  
Poly Lactic Acid ◽  
Weight Changes ◽  
H Nmr ◽  
Left Handed ◽  
Ft Ir

High molecular weight poly (lactic acid) (PLA) was obtained by chain extending with hexamethylene diisocyanate (HDI). The influences of the amount of chain extender, reaction time, and molecular weight changes of prepolymers on the poly(lactic acid) were investigated. PLA prepolymer with a viscosity, average molecular weight (Mη) of 2 × 104 g/mol was synthesized froml-lactide using stannous octoate as the catalyst. After 20 min of chain extension at 175°C, the resulting polymer hadMwof 20.3 × 104 g/mol andMnof 10.5 × 104 g/mol. Both FT-IR and1H-NMR verified that the structure of PLA did not change either before chain extending or after. The optically active characterized that the chain extending-product was left handed. DSC and XRD results showed that both theTgand the crystallinity of PLA were lowered by chain-extension reaction. The crystalline transformation happened in PLA after chain extending, crystallineα′form toαform.

Study on Chain Extension and Modification of Poly(Lactic Acid) by Isophorone Diisocyanate /Polyethylene Glycol

2012 ◽  
Vol 476-478 ◽  
pp. 2067-2070 ◽  
Author(s):  
Zhao Zhang ◽  
Guo Dong Fan ◽  
Hai Yan Yang
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Polyethylene Glycol ◽  
Chain Extension ◽  
Poly Lactic Acid ◽  
Isophorone Diisocyanate ◽  
Molecular Weights ◽  
Peg 400 ◽  
Peg 4000 ◽  
Better Than

Poly(lactic acid)(PLA)was end-capped by isophorone diisocyanate(IPDI) to get PLA-IPDI under the condition of temperature of 176°C and pressure of 0.090 MPa for 13 mins, and then the PLA-IPDI was chain-extended with different molecular weights polyethylene glycol (PEG)-400, PEG-600, PEG-800, PEG-4000 and PEG-6000 to produce a series of block copolymer PLA-IPDI-PEGs. when n(–OH)/n(–NCO)=1.5:1, the molecular weight of PLA-IPDI is maximum. All the copolymer PLA-IPDI-PEGs were characterized by GPC, FTIR, DSC and contact angle testing. The results show that the polymeric degree of PLA-IPDI-PEG-800 is the best and its molecular weight is the biggest. Tg of PLA-IPDI-PEG-800 is the lowest and its hydrophilicity is better than the others modification PLA-IPD-PEGs and pure PLA.

The Preparation of Poly(lactic acid) via Chain Linked Hydroxy-Terminated Lactic Acid Prepolymer

2011 ◽  
Vol 410 ◽  
pp. 337-340
Author(s):  
Suek Songprateepkul ◽  
Suriyan Rakmae ◽  
C. Deeprasertkul ◽  
Nitinat Suppakarn ◽  
Pranee Chumsamrong
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Average Molecular Weight ◽  
Glass Tube ◽  
Acid Value ◽  
Chain Extender ◽  
Hexamethylene Diisocyanate ◽  
Poly Lactic Acid ◽  
Weight Average Molecular Weight ◽  
A Chain

In this work, hydroxyl-terminated lactic acid prepolymer was firstly prepared by adding diethylene glycol in the condensation of lactic acid. Molecular weight, acid value and structure of prepolymer were characterized. The results showed that the prepolymer was hydroxyl-terminated with weight average molecular weight (MW) of 10,000 g/mol. After that, the chain linking polymerization of the prepolymer was carried out in a glass tube at 160 °C for 1 h employing 1,6-hexamethylene diisocyanate (HMDI) as a chain extender. By varying the hydroxyl/isocyanate ratio, it was found that the OH/NCO ratio of 1:2 seemed to be the most suitable ratio which gave PLA with the maximum MW of 93,000 g/mol.

scholarly journals Polypropylene Glycol-Polyoxytetramethylene Glycol Multiblock Copolymers with High Molecular Weight: Synthesis, Characterization, and Silanization

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4317
Author(s):  
Wei Hu ◽  
Lei Wang ◽  
Quanyong Wang ◽  
Anbo Luan ◽  
Yuliang Mai ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Average Molecular Weight ◽  
Chain Extender ◽  
Chain Extension ◽  
Polypropylene Glycol ◽  
Multiblock Copolymers ◽  
Oh Groups ◽  
Potential Applications ◽  
A Chain

The high crystallization at room temperature and high cost of polyoxytetramethylene glycol (PTMG) have become obstacles to its application. To overcome these problems, a segment of PTMG can be incorporated into a block copolymer. In this work, polypropylene (PPO) glycol-polyoxytetramethylene (PPO-PTMG) multiblock copolymers were designed and synthesized through a chain extension between hydroxyl (OH)-terminated PPO and PTMG oligomers. The chain extenders, feed ratios of the catalyst/chain extender/OH groups, reaction temperature, and time were optimized several times to obtain a PPO-PTMG with low crystallization and high molecular weight. Multiblock copolymers with low crystallization and high average molecular weight (Mn = 1.0–1.4 × 104 Dalton) were harvested using m-phthaloyl chloride as the chain extender. The OH-terminated PPO-PTMG multiblock copolymer with high Mn and a functionality near two was further siliconized by 3-isocyanatopropyltrimethoxysilane to synthesize a novel silyl-terminated polyether. This polyether has an appropriate vulcanizing property and potential applications in sealants/adhesive fields.

Processing and characterization of poly(lactic acid) blended with polycarbonate and chain extender

2014 ◽  
Vol 34 (7) ◽  
pp. 665-672 ◽  
Author(s):  
Yottha Srithep ◽  
Wuttipong Rungseesantivanon ◽  
Bongkot Hararak ◽  
Krisda Suchiva
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Gel Permeation Chromatography ◽  
Chain Extender ◽  
Chain Extension ◽  
Morphological Properties ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Commercial Applications ◽  
A Chain

Abstract Currently, use of poly(lactic acid) (PLA) is limited for commercial applications because it has a low heat resistance. In this research, an increase of over 40°C heat distortion temperature (HDT) of PLA alloy was obtained by blending PLA with polycarbonate (PC) and a chain extender (CE). Molecular weight, thermal, mechanical and morphological properties of PLA and PC blend with different CE contents were investigated. Gel permeation chromatography (GPC) results showed that some PLA-PC copolymers were produced and the compatibility of the PLA phase and in the PC phase was improved via the chain extension reaction. In addition, the reaction induced by CE also affected the crystallization behaviors of PLA, as observed from differential scanning calorimetry (DSC) results and the enthalpy of melting of PLA decreased with increasing CE content. The combined effects of the CE increasing molecular weight, improving compatibility and limiting the crystallization behavior of PLA/PC alloy greatly improved the HDT.

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.

Study on the Preparation and Characterization of Carboxyl Terminated Poly(L-Lactic Acid) (PLLA) Prepolymers

2017 ◽  
Vol 872 ◽  
pp. 165-170
Author(s):  
Shi Chao Lu ◽  
Yang Chuan Ke ◽  
Qian Zhou ◽  
Zhao Rui Meng ◽  
Guo Liang Zhang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Average Molecular Weight ◽  
Polymerization Temperature ◽  
Capping Agent ◽  
Molar Amount ◽  
Optimum Reaction ◽  
Catalyst Content ◽  
End Capping

The carboxyl terminated poly (L-lactic acid) (PLLA) prepolymers were prepared via polycondensation of L-lactic acid and 1,6-adipic acid (end capping agent) under the catalyst of stannous octoate. The effects of synthetic condition, such as reaction temperature, amount of catalyst, content of the end capping agent, etc, on the molecular weight of PLLA were discussed. Fourier transform infrared and 1H nuclear magnetic resonance were used to characterize the PLLA prepolymers. The results indicated that the polycondensation was performed under an optimum reaction condition as following: the amount of the catalyst was 500 ppm based on the mass of lactic acid, the amount of the end capping agent was 1% (the molar amount of the lactic acid), and the polymerization temperature was 170 °C. The viscosity-average molecular weight of the product reached 2.826×104 at this polymerization temperature and the yield was 73.34%.

Communication—Monitoring the Average Molecular Weight of Polyethylene Glycol in an Acidic Cu Plating Bath

2016 ◽  
Vol 163 (14) ◽  
pp. D747-D749 ◽  
Author(s):  
Seunghoe Choe ◽  
Myung Jun Kim ◽  
Taeho Lim ◽  
Yu Seok Ham ◽  
Soo-Kil Kim ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Polyethylene Glycol ◽  
Average Molecular Weight ◽  
Plating Bath

scholarly journals Lactic Acid Polymers as Biodegradable Carriers of Fluoroquinolones: An In Vitro Study

1999 ◽  
Vol 43 (3) ◽  
pp. 714-716 ◽  
Author(s):  
Kyriaki Kanellakopoulou ◽  
Maria Kolia ◽  
Antonios Anastassiadis ◽  
Themistoklis Korakis ◽  
Evangelos J. Giamarellos-Bourboulis ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Biodegradable Polymer ◽  
Chronic Osteomyelitis ◽  
In Vitro Study ◽  
Vitro Study ◽  
Bone Infections

ABSTRACT A biodegradable polymer of dl-dilactide that facilitates release of ciprofloxacin or pefloxacin at levels exceeding MICs for the causative microorganisms of chronic osteomyelitis is described. Duration and peak of release were found to depend on the molecular weight of the polymer. Its characteristics make it promising for treating chronic bone infections.

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