Wheat Gluten−Thiolated Poly(vinyl alcohol) Blends with Improved Mechanical Properties

• Published in: Biomacromolecules Vol. 7; no. 10; pp. 2837 - 2844
• Main Authors: Dicharry, Rebecca M, Ye, Peng, Saha, Gobinda, Waxman, Eleanor, Asandei, Alexandru D, Parnas, Richard S
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.10.2006
• Subjects: Acetic Acid - chemistry; Applied sciences; Chemical modifications; Chemical reactions and properties; Compressive Strength; Exact sciences and technology; Glutens - chemistry; Glycerol - chemistry; Magnetic Resonance Spectroscopy; Materials Testing; Models, Chemical; Molecular Weight; Natural polymers; Organic polymers; Physicochemistry of polymers; Polyvinyl Alcohol - chemistry; Proteins; Spectrophotometry, Infrared; Stress, Mechanical; Sulfhydryl Compounds - chemistry; Tensile Strength; Triticum - chemistry; Triticum - metabolism; Water - chemistry; Strengthening; Polymer blends; Vinyl ester copolymer; Mechanical properties; Vinyl alcohol copolymer; Composition effect; Experimental study; Mercaptoacid; Esterification; Intermolecular interaction; Polyvinylalcohol; Chemical modification; Morphology; Preparation; Plant protein; Water absorption; Thiol copolymer; Kinetics; Wheat; Gluten
• ISSN: 1525-7797; 1526-4602
• DOI: 10.1021/bm060432n

A multifunctional macromolecular thiol (TPVA) obtained by esterification of poly(vinyl alcohol) (PVA) with 3-mercaptopropionic acid was characterized by a combination of NMR, IR, transmission electron microscopy (TEM), and differential scanning calorimetry (DSC), and was used as a wheat gluten (WG) reactive modifier. The effect of TPVA molecular weight (M w = 2000, 9500, 50 000, and 205 000) and blend composition (5, 20, and 40% w/w TPVA/WG) on the mechanical properties of compression-molded bars indicates that TPVA/WG blends increase the fracture strength by up to 76%, the elongation by 80%, and the modulus by 25% above WG. In contrast, typical WG additives such as glycerol and sorbitol improve flexibility but decrease modulus and strength. Preliminary investigations of suspension rheology, water uptake, molecular weight distribution and electron microscopy of TPVA/WG and PVA/WG blends illustrate the different protein interactions with PVA and TPVA. Further work is underway to determine whether TPVA and WG form protein conjugates or microphase-separated morphologies.