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 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.

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.

Effect of a chain extender on the properties of poly(lactic acid)/zinc oxide/copper chlorophyll acid antibacterial nanocomposites

2014 ◽  
pp. n/a-n/a ◽  
Author(s):  
Weihua Fan ◽  
Yue Zhao ◽  
Aijing Zhang ◽  
Yukun Liu ◽  
Yanxia Cao ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Lactic Acid ◽  
Chain Extender ◽  
Poly Lactic Acid ◽  
A Chain

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 Smart-Urea-Controlled-Release-Nitrogen-Fertilizer Menggunakan Plastik Biodegradable Poli Asam Laktat Sebagai Carrier

2017 ◽  
Vol 1 (2) ◽  
Author(s):  
Mujtahid Kaavessina ◽  
Chitra Husnabilqis ◽  
Meylani Tri Hardiyanti
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Controlled Release ◽  
Nitrogen Fertilizer ◽  
Average Molecular Weight ◽  
Urea Concentration ◽  
Poly Lactic Acid ◽  
Heating Process ◽  
Toxic Substances ◽  
The Matrix

<p>Poly lactic acid is a polymer that has been developed as an alternative to substitution of conventional polymers. The properties of this polymer are biodegradable in nature and non-toxic substances. These polymers potentially can be used as a matrix for urea carries. The aim of this research was to synthesize poly lactic acid in a low molecular weight. This product can be used as a matrix that urea release controller during the process of fertilization. The methodology consisted of two stages. The first stage was polycondensation of lactic acid and degradability test. Lactic acid was mixed with SnCl2 catalyst 0.1% and heated to 138oC for 24 hours. The second stage was producing in the form of Smart Urea Controlled Release Nitrogen Fertilizer (CRNF). Urea was dissolved in poly lactic acid through a heating process at 150°C to dissolve urea with variation in urea concentration weight of  0.5%; 0.1%; 0.15%; 0.2%; 0.25%; 0.3% and CRNF granulation processes. Finally, the mixture was granulated in ambient temperature. Chemical analysis was done the molecular weight of poly lactic acid. The relationship between intrinsic viscosity  and  molecular  weight  was  used.  The  IR  spectra  (FTIR)  was  used  to  fine molecular structure. The release testing of urea from the matrix of poly lactic acid uses UV-VIS Spectrophotometer. The results showed that the average molecular weight of poly lactic acid is 1149.49 g /gmol. FTIR spectra of CRNF with variation in urea concentration weight showed the presence of groups owned by poly lactic acid and urea. The peaks are</p><p>1627.03 to 1629.92 cm-1 for the -NH group and 3478.77 to 3498.06 cm-1 for group -OH. The existence of these groups proves the existence of urea in CRNF. The release of urea from poly lactic acid occurs by diffusion. It can be seen, when urea in CRNF form immersed in water, the concentration of urea in water increase as well as the increasing immersed time.</p>

Biodegradation Behavior of PLA/PBS Blends

2013 ◽  
Vol 821-822 ◽  
pp. 937-940 ◽  
Author(s):  
Shi Jie Zhang ◽  
Yi Wen Tang ◽  
Li Hua Cheng
Keyword(s):  
Molecular Weight ◽  
Weight Loss ◽  
Lactic Acid ◽  
Average Molecular Weight ◽  
Poly Lactic Acid ◽  
Degradation Behavior ◽  
Butylene Succinate ◽  
Exponential Decrease ◽  
Degradation Time

Poly (butylene succinate) (PBS) was mixed with Poly (lactic acid) (PLA) in the melt state. The PLA/PBS blends with different constitution were produced. The samples were buried in laterite. Samples were dug out of soil after the burial for 10, 20, 30, 40, 50 and 60 days, respectively. The weight loss and molecular weight of the sample were tested. The analysis showed that the nearly exponential decrease in average molecular weight as a function of degradation time. The PLA and PBS have the similar degradation behavior in the soil.

Prediction of Polymer Molecular Weight Distribution from Rheology: Polydimethylsiloxane Blends

2005 ◽  
Vol 480-481 ◽  
pp. 281-286 ◽  
Author(s):  
J. Llorens ◽  
E. Rudé ◽  
R.M. Marcos
Keyword(s):  
Molecular Weight ◽  
Shear Viscosity ◽  
Relaxation Spectrum ◽  
Average Molecular Weight ◽  
Entropy Method ◽  
Dynamic Moduli ◽  
Zero Shear Viscosity ◽  
Weight Average Molecular Weight ◽  
Plateau Modulus ◽  
A Chain

We apply a model that connects rheological properties of linear polymer blends with their molecular weight distributions (MWDs). The model is based on the assumption that the relaxation time, ti, of a chain depends on an average molecular weight, M, which determines the effect of the environment where the molecule reptates, and its own molecular weight according to ti = (kE / 0 N G )·M 3.4 - b·Mi b where kE is the constant of proportionality between zero shear viscosity, ho, and weight average molecular weight, Mw, in unimodal polydisperse systems and 0 N G is the plateau modulus. We deduce that the MWD is related to the relaxation spectrum as H(t) = ( 0 N G /b)·M·W(M). Therefore, the MWD is obtained from the relaxation spectrum, which is deduced from the dynamic moduli, G’(w) and G’’(w), constrained by the plateau modulus, the zero shear viscosity and the steady state compliance, 0 e J . The maximum entropy method has been used to solve the integral equation that provides the relaxation spectra from experimental dynamic moduli. The model has been tested in polydimethylsiloxane blends with weight average molecular weight ranging from 94 to 630 kDa and polydispersity from 1.5 to 3.3. Good agreement is found between experimental and calculated MWDs.

Synthesis and Characterizations of PLLA/PEG Block Copolymers

2010 ◽  
Vol 93-94 ◽  
pp. 198-201 ◽  
Author(s):  
Thai Hien Nguyen ◽  
Atitsa Petchsuk ◽  
Pramuan Tangboriboonrat ◽  
Mantana Opaprakasit ◽  
Alice Sharp ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ring Opening ◽  
Chemical Structure ◽  
Triblock Copolymers ◽  
Hexamethylene Diisocyanate ◽  
Chain Extension ◽  
Poly Lactic Acid ◽  
Multiblock Copolymers ◽  
Molar Ratios ◽  
A Chain

Poly(lactic acid-co-ethylene glycol) (PLLA/PEG) copolymers were synthesized and their properties were characterized. The PLLA/PEG/PLLA triblock copolymers were synthesized by ring-opening polymerization from l-lactide (LLA) and PEG macroinitiator. Stannous octoate, Sn(Oct)2 was used as a catalyst. Effects of molecular weight of PEG (600, 2000 and 4000), LLA/OH molar ratios (95:5, 98:2) and a sequence of addition of the reactants on properties of the copolymers were investigated. The triblock copolymers were subsequently used in a production of multiblock copolymers by reacting with a chain-extending agent, hexamethylene diisocyanate (HMDI). Chemical structure and molecular weight of the copolymers were characterized by 1H-NMR, FTIR and GPC. The results showed that molecular weight of triblock copolymers varied from 4,500 to 10,200. After chain extension, multiblock copolymer with molecular weight of 16,490 was produced. Thermal properties of the copolymers were also examined by DSC.

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.

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