Lactic acid based poly(ester-urethanes): Use of hydroxyl terminated prepolymer in urethane synthesis

Hiltunen, Kari; Seppälä, Jukka; Härkönen, Mika

doi:10.1002/(sici)1097-4628(19970222)63:8<1091::aid-app16>3.0.co;2-9

Cited by 84 publications

(42 citation statements)

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“…29 The compatibilization by adding diisocyanate is based on the addition reaction between the isocyanate group and the PLA hydroxyl group that results in a urethane RANHACOAOHAR 0 group. 28 The possible chemical reactions between the PLA and the diisocyanate are showed in Figure 1(A). 31 The chitosan can also react with the diisocyanate groups due to the presence of numerous hydroxyl and amine groups: the reactions are showed in Figure 1(B).…”

Section: Introductionmentioning

confidence: 99%

Compatibilization method applied to the chitosan‐acid poly(L‐lactide) solution

Suyatma

Copinet

Coma

et al. 2010

J of Applied Polymer Sci

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We are testing the compatibilization of the chitosan/PLA blends by addition of diisocyanate and at studying the effect of several MDI concentrations (0.5 and 2.5% of the global blend mass, w/w). To evaluate the MDI efficiency as a compatibilizer of chitosan/PLA blends, we worked with the following methods: IRTF spectra with higher peak at 1558 cm À1 is due to the ANH bonds that exist in urea and urethane, thermal properties shows that the temperature of the endothermic peaks of the chitosan/PLA blends with MDI is very close to the temperature of pure chitosane and SEM micrography shows that MDI addition decreases the PLA particles size in the chitosan mixture; they also comply with the compatibilization theory. After that the mechanical properties have been characterized: we can notice that the MDI compatibilized chitosan/PLA blends have a higher Young's modulus than the noncompatibilized blends. we are showed that the use of 0.5% MDI is not enough sufficient to obtain a compatibilization, because a part of the MDI can be consumed by water. The addition of MDI increases the performance of the mechanical properties of the blends. Therefore, with this compatibilization, we could obtain some chitosan/PLA blends that would be water-resistant and that would also keep their mechanical properties.

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Section: Introductionmentioning

confidence: 99%

Compatibilization method applied to the chitosan‐acid poly(L‐lactide) solution

Suyatma

Copinet

Coma

et al. 2010

J of Applied Polymer Sci

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“…As we know, the low molecular weight of this aromatic-aliphatic polymer would hinder their appli-cation. As diisocyanate was an effective chain extender for synthesis of high-molecular weight of PLA, 33,34 in this study, we used toluene-2,4-diisocyanate (TDI) as a chain extender to connect PET and PLA segments into the same polymer chain.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of high‐molecular‐weight aliphatic–aromatic copolyesters from poly(ethylene‐co‐1,6‐hexene terephthalate) and poly(L‐lactic acid) by chain extension

Wen-da

Zeng

et al. 2009

J. Polym. Sci. A Polym. Chem.

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A series of aliphatic–aromatic multiblock copolyesters consisting of poly(ethylene‐co‐1,6‐hexene terephthalate) (PEHT) and poly(L‐lactic acid) (PLLA) were synthesized successfully by chain‐extension reaction of dihydroxyl terminated PEHT‐OH prepolymer and dihydroxyl terminated PLLA‐OH prepolymer using toluene‐2,4‐diisoyanate as a chain extender. PEHT‐OH prepolymers were prepared by two step reactions using dimethyl terephthalate, ethylene glycol, and 1,6‐hexanediol as raw materials. PLLA‐OH prepolymers were prepared by direct polycondensation of L‐lactic acid in the presence of 1,4‐butanediol. The chemical structures, the molecular weights and the thermal properties of PEHT‐OH, PLLA‐OH prepolymers, and PEHT‐PLLA copolymers were characterized by FTIR, 1H NMR, GPC, TG, and DSC. This synthetic method has been proved to be very efficient for the synthesis of high‐molecular‐weight copolyesters (say, higher than Mw = 3 × 105 g/mol). Only one glass transition temperature was found in the DSC curves of PEHT‐PLLA copolymers, indicating that the PLLA and PEHT segments had good miscibility. TG curves showed that all the copolyesters had good thermal stabilities. The resulting novel aromatic–aliphatic copolyesters are expected to find a potential application in the area of biodegradable polymer materials. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5898–5907, 2009

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“…A NCO/OH ratio of 1 was used since it proved to be the optimum to obtain linear polymers. 27 The reaction products of both pentablocks with HDI were fully soluble in chloroform, with the yields after reprecipitation in methanol being above 95% (values given in Supporting Information Table S1).…”

Section: Synthesis Of (Pdla-plla-pthf-plla-pdla)-based Multiblock Copmentioning

confidence: 99%

“…Typical chain extenders for polyesters, due to their very high reactivity, are diisocyanates, which react with the terminal hydroxyl groups of the prepolymers, linking the small chains together into poly (ester-urethane) polymers of higher molecular weight. 27,28 As the above ABA triblock copolymers possessed hydroxyl groups at both chain ends, several authors exploited the chain-extension reaction to improve their molecular weight. The chain-extended polymers have a segmented multiblock structure consisting of an alternating sequence of hard, crystalline, blocks and flexible soft segments [e.g., PLLA/poly(trimethylene carbonate), 29 PLLA/poly(e-caprolactone-cotrimethylene carbonate), 30 PLLA/poly(ethylene oxide), 31 PLLA/poly(e-caprolactone), 32,33 PLLA/poly(isobutylene), 34 and PLLA/poly(butylene adipate) 35 ], whose composition can be easily manipulated at the level of the triblocks while attaining high molecular weights.…”

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confidence: 99%

Novel poly(l -lactide)/poly(d -lactide)/poly(tetrahydrofuran) multiblock copolymers with a controlled architecture: Synthesis and characterization

Gardella¹,

Cavallo²,

Colonna

et al. 2014

J. Polym. Sci. Part A: Polym. Chem.

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Novel poly(l‐lactide) (PLLA)/poly(d‐lactide) (PDLA)/poly(tetrahydrofuran) (PTHF) multiblock copolymers with designed molecular structure were synthesized by a two‐stage procedure. Well‐defined PDLA‐PLLA‐PTHF‐PLLA‐PDLA pentablock copolymers were prepared by sequential ring opening polymerization of l‐ and d‐lactides starting from PTHF glycol, with the length of the (equimolar) PLLA and PDLA blocks being varied. Then, these dihydroxyl‐terminated pentamers were transformed into multiblock copolymers by melt chain‐extension with hexamethylene diisocyanate–being the first time that the coupling of pentablock units is reported. The successful formation of macromolecular chains with a multiblock and well‐defined architecture was demonstrated by 1H NMR spectroscopy. The thermal properties and structuring of the resulting materials were investigated by means of DSC and WAXD measurements and DMA analysis. Stereocomplexation was found to be promoted during solution and melt crystallization. This approach affords materials combining the high rigidity and strength (other than improved thermal resistance) of the hard stereocomplex crystallites with the flexibility imparted by the soft block, whereby their properties can be finely tailored through the composition of the basic pentablock units without limitations on the final molecular weight. The adopted reaction conditions make this process highly appealing in view of the possibility to perform it in extruder. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 3269–3282

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Lactic acid based poly(ester-urethanes): Use of hydroxyl terminated prepolymer in urethane synthesis

Cited by 84 publications

References 1 publication

Compatibilization method applied to the chitosan‐acid poly(L‐lactide) solution

Compatibilization method applied to the chitosan‐acid poly(L‐lactide) solution

Synthesis of high‐molecular‐weight aliphatic–aromatic copolyesters from poly(ethylene‐co‐1,6‐hexene terephthalate) and poly(L‐lactic acid) by chain extension

Novel poly(l -lactide)/poly(d -lactide)/poly(tetrahydrofuran) multiblock copolymers with a controlled architecture: Synthesis and characterization

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