Synthesis of Sustainable Polymers from Vegetable Oil: Applications in Coatings and Nanoparticle Surface Modification
Abstract
Polymeric materials are increasing being used in many household, industrial, and health and personal care products. These materials, being either non-degradable or slow degradable, remain in the environment for a long time and are posing increasingly significant threats to the ecosystem components including mammals, birds, fish, reptiles, and crustaceans. Renewable resource based materials are the best raw materials for the development of sustainable products. Vegetable oil and polyglycol based novel copolymers have been synthesized in this research. Poly(2-VOES-r-TEGEVE) copolymers were synthesized from 2-(vinyloxyethyl) soyate (2-VEOS) and tri(ethylene glycol) ethyl vinyl ether (TEGEVE) via cationic polymerization. They were used in waterborne coating as self-dispersible polymers and as surfmers. Four different copolymers were synthesized having 2-VOES wt% as 10, 15, 25, 50 and rest being TEGEVE. In addition to that water insoluble poly(2-VOES) copolymers were synthesized from soybean oil. All copolymers were used as self-dispersible polymers and their coating property were analyzed by measuring glass transition temperature, drying time, gloss, transparency, contact angle, hysteresis, tensile strength, and hardness. Results showed that the coatings can be cured by autoxidation drying process within 6.1 to 8.2 h. Results also showed high transparency (coated in glass panel) with maximum 2% absorbance which is comparable to uncoated substrate (clean glass). Copolymer having 2-VOES wt% 15 and 50 were used as surfmers to disperse poly(2-VOES) and they were cured using autoxidation method. Results showed that the curing of film can be achieved within 2.6 to 8.0 h. High gloss and transparency confirmed that the surfmers get copolymerized with poly(2-VOES). Another set of poly(2-VOES-r-TEGEVE) copolymers with 2-VOES wt% 15, 25, 50, 75 and 85 were synthesized and then functionalized with a carboxyl group. These carboxyl functionalized polymer were used to coat nanoscale zero-valent iron (NZVI) to enhance their colloidal stability in aqueous media with an objective of using the coated particles for groundwater remediation. Structure property analysis of the coated NZVI showed that carboxyl functional copolymer with 15 wt% 2-VOES and 85 wt% TEGEVE had the best colloidal stability of the coated NZVI (CNZVI). Treatability study with CNZVI was carried out using trichloroethylene (TCE) and arsenic [As(V)] as model contaminants. Treatability data indicated that CNZVI can degrade 85 % of TCE (initial concentration 15 mgL-1) within 6 h and remove 99% of As(V) (initial concentration 15 mgL-1) within 0.5 h. Results also showed that CNZVI has higher contaminant (TCE and arsenic) removable rate compared to NZVI. The biodegradation behaviors of carboxyl functionalized poly(2-VOES-r-TEGEVE) copolymers were analyzed by respirometric, microbial growth, and gel permeation chromatography (GPC) studies. Respirometic test confirmed 90% degradations of carboxyl functionalized poly(2-VOES-r-TEGEVE) copolymers within 28 d. Microbial growth and GPC studies also support the data obtained from respirometic tests.