Novel Environmentally Friendly Copolymers Carboxymethyl Starch Grafted Poly(Lactic Acid)

• Published in: Journal of polymers and the environment Vol. 21; no. 2; pp. 461 - 471
• Main Authors: Lipsa, Rodica, Tudorachi, Nita, Vasile, Cornelia, Chiriac, Aurica, Grigoras, Anca
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-06-2013; Springer; Springer Nature B.V
• Subjects: Applied sciences; Biodegradation; Chemical synthesis; Chemistry; Chemistry and Materials Science; Copolymers; Differential scanning calorimetry; Environmental Chemistry; Environmental Engineering/Biotechnology; Exact sciences and technology; Graft copolymers; Industrial Chemistry/Chemical Engineering; Light scattering; Materials Science; Molecular weight; Natural polymers; Original Paper; Physicochemistry of polymers; Plastics; Polymer Sciences; Polymerization; Polymers; Starch; Starch and polysaccharides; Starches; Thermal properties; Toluene; Carboxymethyl starch-g-poly(lactic acid); Graft copolymerization; Biodegradable copolymers; Graft copolymer; Molecular structure; Lactic acid copolymer; Crystallinity; Experimental study; Grafting; Thermal stability; Morphology; Preparation; Oside polymer; Polyacid; Acid copolymer; Starch derivative
• ISSN: 1566-2543; 1572-8919; 1572-8900
• DOI: 10.1007/s10924-012-0470-1

Modified natural polymers have been gaining increasing scientific interest for many years. In this study carboxymethyl starch (CMS) was grafted with L(+)-lactic acid (LA) in different molar ratios CMS/LA (1/36, 1/22 and 1/12), resulting carboxymethyl starch-g-poly(lactic acid) (CMS-g-PLA) copolymers. The grafting reaction was carried out by solution polycondensation procedure in toluene and stannous 2-ethyl hexanoate Sn(Oct)
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as catalyst was utilized. Poly(lactic acid) (PLA) was synthesized in the same conditions with the copolymers for comparative analyses of the physico-chemical and thermal properties. The copolymers and PLA were structurally and morphologically characterized by FT-IR,
1
H-NMR spectroscopy, WAXD and SEM analyses, taking CMS as reference. The molecular weight of the copolymers, CMS and PLA were determined, using a dynamic light scattering technique. The thermal behavior of the products was studied by DSC and TG-DTG analyses. The CMS-g-PLA graft copolymers exhibited lower Tg and thermal stability than pure CMS.