روغن نباتی و مواد زیستی به عنوان پلی استر ساز PVC Epoxidized vegetable oil and bio-based materials as PVC plasticizer

INTRODUCTION Over the last decade, poly(vinyl chloride) (PVC) has been one of the largest commodity thermoplastics used for numerous commercial and domestic applications, such as children toys, infants supply, medical supplies, packaging materials, and others.1,2 PVC has hard and brittle characteristics as a result of dipole present on each CACl bond, where an interaction among PVC chain exists that restricts chain motility.3 In order to enhance PVC characteristics, a compatible plasticizer is to be added to adjust its mechanical and thermal properties.4,5 This is performed via spacing out the PVC molecules to reduce the interaction between segments of polymer chains which leads to lowering the adhesion among molecules.2,3,6,7,11 Furthermore, adding a plasticizer to PVC lowers both the elasticity modulus and the glass transition point which leads to an enhancement in PVC processing properties.3,8,11 However, most plasticizers are not chemically bonded with PVC polymer chains; this allows them to leach from products into surrounding media.3,9 Hence, studying the exposure to these compounds has become an essential part of maintaining public health, and preventing associated adverse effects.10 There are many plasticizers used in PVC processing, one of those plasticizers is phthalate esters. Phthalate esters are petroleum-based products which are the most commonly used plasticizers in PVC processing. They represent more than 80% of PVC plasticizer market share.3,11 Phthalate esters group has a lot of members that are used in industry such as diisodecylphthalate (DIDP), di-2 ethyl hexyl phthalate (DEHP), di-octyl phthalate (DOP), and di-isononyl phthalate (DINP). All the industry-used members have very similar chemical and physical properties.12 Most of phthalate plasticizers are wellknown to be toxic, and may cause disorders in human reproduction system and endogenous hormone; owing to their migration from polymer matrix.3,13 Thus, it is recommended to use bio-compatible and sustainable alternative instead of phthalate esters. This would be from renewable resources and more secure materials than commercial phthalate.3,11 This review article depicts the harmful health effects of using commercial phthalate esters plasticizers in PVC products. It also describes two approaches; the first is a conventional production approach that uses chemical catalyst to obtain ester or epoxy from substrates such as vegetable oils.