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Author: search.filters.author.Loungvanidprapa, PittayaSubject: search.filters.subject.Ring-opening polymerization

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    Synthesis of poly(ethylene terephthalate-co-isophthalate) via ring-opening polymerization of their cyclic oligomers
    (2008-10-01)
    Monvisade, Pathavuth
    ;
    Loungvanidprapa, Pittaya
    Syntheses of poly(ethylene terephthalate-co-isophthalate) (PET-co-PEI) were achieved via ring-opening copolymerization of corresponding cyclic oligoesters. The ring-opening polymerization (ROP)-PET-co-PEI were prepared by equilibrating an equimolar amount of cyclic oligo(ethylene terephthalate) and cyclic oligo(ethylene isophthalate) using di-n-butyltin oxide catalyst under high concentration conditions at 270 and 290°C for 8 and 12 h. The copolyesters were obtained in yields of up to 91% with the inherent viscosity (η <inf>inh</inf>) of up to 2.89 dl/g indicating the drastically high molecular weight compared with the conventional and ROP routes for the synthesis of PEI. The differential scanning calorimetry data of ROP-PET-co-PEI showed the melting temperatures above 400°C indicated the potential used in high temperature application. © 2008 Springer Science+Business Media B.V.
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    Synthesis of poly(ethylene adipate) and poly(ethylene adipate-co-terephthalate) via ring-opening polymerization
    (2007-08-01)
    Monvisade, Pathavuth
    ;
    Loungvanidprapa, Pittaya
    Syntheses of poly(ethylene adipate) (ROP-PEA) and poly(ethylene adipate-co-terephthalate) (ROP-PEA-co-PET) were achieved via ring-opening polymerization of corresponding cyclic oligoesters. In case of ROP-PEA, cyclic oligo(ethylene adipate) (C-OEA) was equilibrated in the presence of di-n-butyltin oxide as a catalyst under high-concentration conditions at 180 and 200 °C for 1-24 h. The polymer products were obtained in yields up to 100% with the over(M, -)<inf>n</inf> and over(M, -)<inf>w</inf> in the ranges of 3000-23 000 g/mol and 5000-60 000 g/mol, respectively. The ROP-PEA-co-PET was prepared by equilibrating an equimolar amount of C-OEA and cyclic oligo(ethylene terephthalate) (C-OET) using di-n-butyltin oxide catalyst under high-concentration conditions at 250 °C for 24 h. The copolyester produced was obtained in yield of 97% with the over(M, -)<inf>n</inf> and over(M, -)<inf>w</inf> of 18 000 and 46 000 g/mol, respectively. <sup>1</sup>H NMR spectrum of ROP-PEA-co-PET showed two new proton signals of ethylene unit representing the existence of heterolinkage with different chemical environment in the copolymer. This indicated the random transesterification of C-OEA and C-OET resulting in random structure in copolyester. In addition, the result of ROP-PEA-co-PET from DSC showed the glass transition temperature in the values of -8 °C with no melting temperature indicating thermoplastic elastomeric behavior. © 2007 Elsevier Ltd. All rights reserved.