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Article

Preparation and Characterization of Whey Protein-Based Polymers Produced from Residual Dairy Streams

1
Department of Chemical Engineering, Masdar City Campus, Khalifa University, Abu Dhabi 54224, UAE
2
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
3
Department of Chemical Engineering, Biotechnology and Environmental Technology, University of Southern Denmark, 5230 Odense, Denmark
*
Authors to whom correspondence should be addressed.
Polymers 2019, 11(4), 722; https://doi.org/10.3390/polym11040722
Received: 19 February 2019 / Revised: 22 March 2019 / Accepted: 27 March 2019 / Published: 19 April 2019
(This article belongs to the Special Issue Natural Compounds for Natural Polymers)
The wide use of non-biodegradable, petroleum-based plastics raises important environmental concerns, which urges finding alternatives. In this study, an alternative way to produce polymers from a renewable source—milk proteins—was investigated with the aim of replacing polyethylene. Whey protein can be obtained from whey residual, which is a by-product in the cheese-making process. Two different sources of whey protein were tested: Whey protein isolate (WPI) containing 91% protein concentration and whey protein concentrate (WPC) containing 77% protein concentration. These were methacrylated, followed by free radical polymerization with co-polymer poly(ethylene glycol) methyl ether methacrylate (PEGMA) to obtain polymer sheets. Different protein concentrations in water (11–14 w/v%), at two protein/PEGMA mass-ratios, 20:80 and 30:70, were tested. The polymers made from WPI and WPC at a higher protein/PEGMA ratio of 30:70 had significantly better tensile strength than the one with lower protein content, by about 1–2 MPa (the best 30:70 sample exhibited 3.8 ± 0.2 MPa and the best 20:80 sample exhibited 1.9 ± 0.4 MPa). This indicates that the ratio between the hard (protein) and soft (copolymer PEGMA) domains induce significant changes to the tensile strengths of the polymer sheets. Thermally, the WPI-based polymer samples are stable up to 277.8 ± 6.2 °C and the WPC-based samples are stable up to 273.0 ± 3.4 °C. View Full-Text
Keywords: protein-based polymer; copolymerization; whey protein; mechanical properties; PEGMA protein-based polymer; copolymerization; whey protein; mechanical properties; PEGMA
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MDPI and ACS Style

Chalermthai, B.; Chan, W.Y.; Bastidas-Oyanedel, J.-R.; Taher, H.; Olsen, B.D.; Schmidt, J.E. Preparation and Characterization of Whey Protein-Based Polymers Produced from Residual Dairy Streams. Polymers 2019, 11, 722. https://doi.org/10.3390/polym11040722

AMA Style

Chalermthai B, Chan WY, Bastidas-Oyanedel J-R, Taher H, Olsen BD, Schmidt JE. Preparation and Characterization of Whey Protein-Based Polymers Produced from Residual Dairy Streams. Polymers. 2019; 11(4):722. https://doi.org/10.3390/polym11040722

Chicago/Turabian Style

Chalermthai, Bushra, Wui Y. Chan, Juan-Rodrigo Bastidas-Oyanedel, Hanifa Taher, Bradley D. Olsen, and Jens E. Schmidt 2019. "Preparation and Characterization of Whey Protein-Based Polymers Produced from Residual Dairy Streams" Polymers 11, no. 4: 722. https://doi.org/10.3390/polym11040722

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