Melt Polycondensation and Analysis of Hydroxyl-Terminated Poly(L-lactic Acid) Using Small Molecular Diols as Terminating Agents

2013 ◽  
Vol 328 ◽  
pp. 890-894
Author(s):  
Jing Che ◽  
Rong Jie Yang
Keyword(s):  
Lactic Acid ◽  
Ethylene Glycol ◽  
Gel Permeation Chromatography ◽  
Catalyst System ◽  
Molecular Weights ◽  
H Nmr ◽  
Melt Polycondensation ◽  
Direct Melt Polycondensation ◽  
Group Structures ◽  
End Group

The synthesis of hydroxyl-terminated poly (L-lactic acid) (PLLA) by direct melt polycondensation of L-lactic acid and use of small molecular diols as terminating agents was investigated. L-lactic acid was dewatered to prepare the dehydrated prepolymer at first. Then PLLA was prepared through melt polycondensation in a melt with catalyst system including TSA, SnCl2and Sn (Oct)2. Finally, ethylene glycol, 1,4-butanediol, and 1,8-octanediol, respectively, were used in hydroxyl termination of the PLLA. The molecular weights and end-group structures of all products were characterized by gel permeation chromatography (GPC) and1H-NMR. DSC and Disc Polarimeter were used to characterize crystallinity and racemization, respectively. The results show that two kinds of hydroxyl-terminated PLLA polymers were obtained: complete hydroxyl-terminated PLLA prepared by using ethylene glycol or 1,4-butanediol, incomplete hydroxyl-terminated PLLA prepared by using 1,8-octanediol or combination of two kinds of diols. Combination of ethylene glycol or 1,4-butanediol with 1,8-octanediol can reach high hydroxyl termination of PLLA, and maintain the molecular weight by decrease of alcoholysis at the same time.1H-NMR was found as an effective estimating way for extents of reactions. The hydroxyl-terminating reactions of PLLA by the diols reduced the crystallinity and resulted in racemization to some extent.

Research on the Modification of Poly(L-Lactic Acid) by Glucose via Direct Melt Polycondensation

2011 ◽  
Vol 311-313 ◽  
pp. 1106-1109 ◽  
Author(s):  
Shi He Luo ◽  
Shi Qin Yu ◽  
Jian Xiao Li ◽  
Zhao Yang Wang
Keyword(s):  
Drug Delivery ◽  
Lactic Acid ◽  
Feed Ratio ◽  
Biodegradable Material ◽  
Drug Delivery Application ◽  
H Nmr ◽  
Melt Polycondensation ◽  
Molar Feed Ratio ◽  
Direct Melt Polycondensation

Directly using L-lactic acid (L-LA) and glucose (Glu) as the starting materials, novel biodegradable material poly(L-lactic acid-co-glucose) [P(L-LA-co-Glu)] was synthesized via direct melt polycondensation. The copolymers P(L-LA-co-Glu)s at different molar feed ratios were characterized by FTIR,1H-NMR, GPC, DSC and XRD. All poly(L-lactic acid) modified by Glu was partly crystalline. And their Mw, Tm, and crystallinity basically increased with the increase of the molar feed ratio n(L-LA) : n(Glu). When n(Glu) : n(L-LA) was 1 : 750, the biggest Mw was 5900 Da, and all Mwcould meet the requirement for drug delivery application.

Synthesis and Characterization of Poly (L-Lactic acid) Containing the Azobenzene Mesogens

2011 ◽  
Vol 181-182 ◽  
pp. 185-188
Author(s):  
Run Tao Dong ◽  
Qing Bin Xue ◽  
Ling Min Sun ◽  
Quan Xuan Zhang
Keyword(s):  
Lactic Acid ◽  
Optical Rotation ◽  
Gel Permeation Chromatography ◽  
Helical Structure ◽  
Feed Ratio ◽  
Scanning Calorimetry ◽  
Molecular Weights ◽  
H Nmr ◽  
Azobenzene Mesogens

A series of azobenzene containing group Poly (L-lactic acid) (PLLA) were synthesized by Ring-Opening Polymerization of L-lactide (L-LA) catalysted by Sn (Oct)2initiated by alcohol-OH containing the azobenzene chromophores. Their molecular weights were well controlled by the feed ratio as characterized by Gel Permeation Chromatography (GPC) and1H NMR Spectrometry and agreed well with theoretical values. The thermal properties and liquid crystal phases were investigated by Differential Scanning Calorimetry (DSC), polarized optical microscopy (POM) and X-ray Diffraction (XRS) measurements. Cis-trans photoisomerization behavior of the polymers in the solutions and the films were studied with UV irradiation. By the Circular Dichroism Spectroscopy (CD) characterization of the solutions and films of the polymer, the PLLA segments show huge optical rotation power in helical structure.

scholarly journals Synthesis of Dextran/Methoxy Poly(ethylene glycol) Block Copolymer

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Young-Il Jeong ◽  
Dong-Gon Kim ◽  
Dae-Hwan Kang
Keyword(s):  
Block Copolymer ◽  
Ethylene Glycol ◽  
Gel Permeation Chromatography ◽  
Hydroxyl Group ◽  
Poly Ethylene Glycol ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Glucose Molecule ◽  
Poly Ethylene ◽  
End Group

We synthesized a block copolymer composed of dextran and methoxy poly(ethylene glycol) (mPEG). To accomplish this, the end group of dextran was modified by reductive amination. The aminated dextran (Dextran-NH2) showed the intrinsic peaks of both dextran at 3~5.5 ppm and hexamethylene diamine at 1~2.6 ppm at1H nuclear magnetic resonance (NMR) spectrum. The amino end group of dextran was conjugated with mPEG to make the block copolymer consisting of dextran/mPEG (abbreviated as DexPEG). The synthesized aminated dextran and DexPEG were characterized using1H NMR and gel permeation chromatography (GPC). The molecular weight and conjugation yield were estimated by comparing the intensity ratio of the proton peaks of the glucose molecule (4.9 ppm and 3.3~4.0 ppm) to that of the ethylene group of mPEG (3.7 ppm). Abundant hydroxyl group in the dextran chain can be used as a source of bioactive agent conjugation.

scholarly journals Preparation, Mechanical, and Thermal Properties of Biodegradable Polyesters/Poly(Lactic Acid) Blends

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Peng Zhao ◽  
Wanqiang Liu ◽  
Qingsheng Wu ◽  
Jie Ren
Keyword(s):  
Lactic Acid ◽  
Gel Permeation Chromatography ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Scanning Calorimetry ◽  
Butylene Succinate ◽  
Biodegradable Polyesters ◽  
H Nmr ◽  
Melt Polycondensation ◽  
Twin Screw

Series of biodegradable polyesters poly(butylene adipate) (PBA), poly(butylene succinate) (PBS), and poly(butylene adipate-co-butylene terephthalate) (PBAT) were synthesized successfully by melt polycondensation. The polyesters were characterized by Fourier transform infrared spectroscopy (FTIR),1H-NMR, differential scanning calorimetry (DSC), and gel permeation chromatography (GPC), respectively. The blends of poly(lactic acid) (PLA) and biodegradable polyester were prepared using a twin screw extruder. PBAT, PBS, or PBA can be homogenously dispersed in PLA matrix at a low content (5–20 wt%), yielding the blends with much higher elongation at break than homo-PLA. DSC analysis shows that the isothermal and nonisothermal crystallizabilities of PLA component are promoted in the presence of a small amount of PBAT.

scholarly journals Sizing and Thermal Stability of Prepared Tetraaminophthalocyaninatocopper(II) Derivatives-grafted Polymers

2016 ◽  
Vol 13 (2) ◽  
pp. 221-234
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thermal Stability ◽  
Ethylene Glycol ◽  
Group Analysis ◽  
Condensation Polymerization ◽  
Grafted Polymers ◽  
Poly Ethylene Glycol ◽  
Molecular Weights ◽  
Poly Ethylene ◽  
Thermal Stability Of ◽  
End Group

Different polymers were prepared by condensation polymerization of sebacic anhydride and adipic anhydride with ethylene glycol and poly(ethylene glycol). Their number average molecular weights were determined by end group analysis. Then, they were grafted on the prepared phthalocyaninatocopper(II) compounds with the general formula (NH2)4PcCu(II) having amino groups of 3,3',3'',3'''- or 4,4',4'',4'''- positions. All prepared polymers, compounds, and phthalocyaninatocopper(II)-grafted polymers were characterized by FTIR. The sizing measurements were carried out in 3,3',3'',3'''- (NH2)4PcCu(II) and 4,4',4'',4'''- (NH2)4PcCu(II) compounds with and without grafting polymers. The results showed that the grafting process led to decreasing in particle size and increasing in surface area. The grafting process was reflected positively on the thermal degradation of 3,3',3'',3'''- (NH2)4PcCu(II) and 4,4',4'',4'''- (NH2)4PcCu(II) grafted polymers. They had higher thermal stability accompanied with higher char residue and T50% weight loss with 3,3',3'',3'''-(NH2)4PcCu(II) and their grafted polymers being the best.

ATRP Synthesis of PS-b-PtBMA and Preparation of Porous Film

2013 ◽  
Vol 364 ◽  
pp. 679-683
Author(s):  
Chang Hao Yan ◽  
Zhi Jiao Zhang ◽  
Hai Yan Chen ◽  
Zhong Yi Xie ◽  
Ting Zhu ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Atom Transfer Radical Polymerization ◽  
Radical Polymerization ◽  
Catalyst System ◽  
Porous Film ◽  
Atom Transfer ◽  
H Nmr ◽  
Breath Figure ◽  
Breath Figure Method ◽  
End Group

The polystyrene with end group of Br was synthesized by using MBrP as the initiator, CuBr/ PMDETA as the catalyst system according to atom transfer radical polymerization (ATRP). The effect of reaction temperature was studied and the system was confirmed as the active polymerization. Then PS-Br and CuBr/ PMDETA were respectively used as macroinitiator and catalyst to polymerize tBMA according to atom transfer radical polymerization (ATRP). The structure of the product was characterized by GPCFTIR1H-NMR. The amphiphilic block copolymer was obtained after hydrolysis. And the honeycomb porous film was prepared by PS-b-PMAA through using breath figure method.

Synthesis of Star-Shaped PLA via Direct Melt Polycondensation: 1. Using L-LA as Starting Material

2010 ◽  
Vol 152-153 ◽  
pp. 1236-1239
Author(s):  
Zhao Yang Wang ◽  
Chao Xu Mao ◽  
Yu Fen Luo ◽  
Shi He Luo ◽  
Jun Min Nan
Keyword(s):  
Drug Delivery ◽  
Lactic Acid ◽  
Low Cost ◽  
Starting Material ◽  
Feed Ratio ◽  
Simple Process ◽  
The Core ◽  
Melt Polycondensation ◽  
Molar Feed Ratio ◽  
Direct Melt Polycondensation

Using 1,3,5-benzenetrioxyundecanol (mTU) as the core, and L-lactic acid (L-LA) as starting material, a novel star-shaped poly(L-lactic acid) (SPLLA) was synthesized via direct melt polycondensation with simple process and low-cost. The obtained biodegradable polymer SPLLA was systematically characterized with the intrinsic viscosity [η], FTIR, 1H-NMR, GPC and XRD. The Mw, Tg, Tm, ΔH, crystallinity, crystallite size of all SPLLA basically increased with the increase of the molar feed ratio n(L-LA) : n(mTU). When n(L-LA) : n(mTU) was 500:1, the biggest Mw was 8600, but all Mw meet the requirement for drug delivery application.

Plasticizing effect of poly(ethylene glycol)s with different molecular weights in poly(lactic acid)/starch blends

2015 ◽  
Vol 132 (16) ◽  
pp. n/a-n/a ◽  
Author(s):  
Yunan Yu ◽  
Yan Cheng ◽  
Jiawei Ren ◽  
Erping Cao ◽  
Xiaowei Fu ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Ethylene Glycol ◽  
Poly Lactic Acid ◽  
Poly Ethylene Glycol ◽  
Molecular Weights ◽  
Starch Blends ◽  
Poly Ethylene
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