From an industrial point of view, the use of new nontoxic and biodegradable plasticizers coming from natural resources is an interesting alternative to traditional plasticizers based on phthalates. In this study, two types of epoxidized fatty acids esters (EFAE) with different molecular weight have been used in order to produce flexible PVC with low toxicity. Different amounts of EFAE 201 and 401 have been considered in this study. Mechanical and thermal properties have been determined and morphology of fracture surface has been studied by scanning electron microscopy.Keywords: polyvinyl chloride; natural plasticizer; mechanical properties; thermal properties, 3
1.-IntroductionIn recent years, there has been an increasing interest in the environmental policies in the polymeric materials sector. This awareness has been presented by consumers, manufacturers and even legislators [1]. This has motivated important lines of work in the development and applications of polymeric materials which are environmentally friendly, low toxicity and easily recyclable [2]. Within this research field, a marked interest has been showed in the improving of the formulations of one of the most widely consumed thermoplastics worldwide as the polyvinyl chloride (PVC), more specifically, the flexible polyvinyl chloride [3,4]. The use of this thermoplastic is especially sensitive to environmental impact and toxicity problems, since it is widely used in sectors such as plastic toys, childcare, food, packaging, medicalpharmacological... It has to be considered that PVC is obtained from the addition of plasticizers to the vinyl polymer. Some additives and specially plasticizers normally suffer a migration phenomenon to the substances or elements that are in contact [5][6][7][8].So, the contact substances can suffer contamination, and in the worst cases, there is a risk of toxicity and there are health risks to the final consumer [9]. PVC traditional plasticizers based in phthalates are traditionally widely used by the plastic industry. Currently its use is being challenged due to the migration phenomenon, which results in toxicity problems [10,11]. In order to improve the consumer's health protection and safety, the relevant authorities have developed specific regulations regarding the use of phthalates as PVC plasticizers [12,13] Alternative plasticizers have been developed in order make more flexible the polyvinyl chloride. These plasticizers are characterized by low environmental impact, low migration and low toxicity in applications sensitive to this phenomenon, such as use in childcare items [16,17]. Plasticizers from natural products are a very interesting alternative as a replacement of phthalates traditionally used in the plastics industry.Interesting research works have been developed successfully for the applicability in the industry of plastic processing [18,19]. These investigations use citrates, benzoates and carboxylates as alternative plasticizers since they have very similar behavior to PVC flexible with phthalates [2...