title: Inducing PLA/starch compatibility through butyl-etherification of waxy and high amylose starch.
abstract: In this study, waxy and high amylose starches were modified through butyl-etherification to facilitate compatibility with polylactide (PLA). Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and wettability tests showed that hydrophobic butyl-etherified waxy and high amylose starches were obtained with degree of substitution values of 2.0 and 2.1, respectively. Differential scanning calorimetry, tensile testing, and scanning electron microscopy (SEM) demonstrated improved PLA/starch compatibility for both waxy and high amylose starch after butyl-etherification. The PLA/butyl-etherified waxy and high amylose starch composite films had higher tensile strength and elongation at break compared to PLA/non-butyl-etherified composite films. The morphological study using SEM showed that PLA/butyl-etherified waxy starch composites had a more homogenous microstructure compared to PLA/butyl-etherified high amylose starch composites. Thermogravimetric analysis showed that PLA/starch composite thermal stability decreased with starch butyl-etherification for both waxy and high amylose starches. This study mainly demonstrates that PLA/starch compatibility can be improved through starch butyl-etherification.
authors.affiliation: DST/CSIR National Centre for Nanostructured Materials, Council for Scientific and Industrial Research, 1-Meiring Naude Road, Brummeria, Pretoria 0001, South Africa; Department of Applied Chemistry, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa.
authors.forename: Obiro Cuthbert
authors.initials: OC
authors.lastname: Wokadala
authors.affiliation: Department of Food Science, University of Pretoria, Pretoria, South Africa.
authors.forename: Naushad Mohammad
authors.initials: NM
authors.lastname: Emmambux
authors.affiliation: DST/CSIR National Centre for Nanostructured Materials, Council for Scientific and Industrial Research, 1-Meiring Naude Road, Brummeria, Pretoria 0001, South Africa; Department of Applied Chemistry, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa; Department of Food Science, University of Pretoria, Pretoria, South Africa. Electronic address: rsuprakas@csir.co.za.
authors.forename: Suprakas Sinha
authors.initials: SS
authors.lastname: Ray
mesh_terms: D000687:Amylopectin / Q000737:chemistry; D000688:Amylose / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D004987:Ethers / Q000737:chemistry; D019344:Lactic Acid / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D011091:Polyesters; D011108:Polymers / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013213:Starch / Q000737:chemistry*; D013718:Tensile Strength; D013818:Thermogravimetry
chemical_list: D001672:Biocompatible Materials; D004987:Ethers; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide); D013213:Starch; D000688:Amylose; D000687:Amylopectin
keywords: Biopolymer composites; Compatibility; Modified starch; Polylactic acid (polylactide)