The preparation of linseed oil fatty acid modified polystyrene

Vegetable oils are raw material resources that enable to synthesize polymers in oil based organic coating industry. However, oils could not be used without modification for coating purposes. Linseed oil has an iodine value in the 185-190 region that is a good choice for modification of polystyrene polymers because of its naturally drying capacity. Because of brittle characteristic of polystyrenes, they could not be used in coating applications. However they could form adhesive, tough films when modificated with vegetable oils [1-2]. On the other hand, benzyl chloride bonds of 4-chloromethyl styrene (CMS) are made nucleophilic substitutions possible. In this thesis, the aim is to eliminate the fragility character of polystyrene by the way of modification via linseed oil fatty acid for being used as a coating material in industry. For this purpose, first of all, linseed oil fatty acid (FA) mixture was prepared by saponification reaction. Linseed oil was boiled with 10% KOH solution then, obtained soap mixture was turned into fatty acid mixture by acidulation with sulfate acid solution. In the next step, polymer of Styrene-co-4-Chloromethyl Styrene [P(St-co-CMS)] was synthesized by using Nitroxide Mediated Radical Polymerization (NMRP) method to control polymerization process and to obtain narrow molecular weight distributions. The molecular weights and polydispersities of the copolymers were identified by Gel Permeation Chromatography (GPC). The number of functional chloromethyl groups (CH2-Cl) were calculated by using the results of Nuclear Resonance Spectroscopy (1H-NMR) and GPC. According to results of the characterization studies (1H-NMR, GPC), number of 4-CMS units in each copolymer chain were calculated as 1.373 mole and 2.3946 mole for P(St-co-CMS)1 and P(St-co-CMS)2, respectively. In the step of modification with FA, nucleophilic substitution reaction was achieved having regard to the number of functional CH2-Cl groups in 1 mole P(St-co-CMS)2 chain. FA attached to the P(St-co-CMS)2 backbone by substitution reaction. The reaction was achieved between chloro group and acid group in the presence of K2CO3. For the characterization studies GPC, 1H-NMR and Fourier Transform Infrared Spectroscopy (FT-IR) were applied. The film properties of the samples were specified according to ASTM standarts. Although P(St-co-CMS)2-FA appears to be a feebleness material for coating, to decrease the fragility, polymer of CMS (PCMS) was synthesized. But, modification products with PCMS was not formed since gelation occurred due to the high molecular weight and high chlorine group numbers.