Several published studies have evaluated the problems associated with the utilization of biodiesel obtained from safflower (Carthamus tinctorius L.) oil due to the low oxidative stability, caused by the high content of unsaturated fatty acids. Thus, this study aimed at the extraction of safflower seed oil and its use as an unsaturation source to obtain a synthetic antioxidant. The synthesis of this phenolic additive was done by modifying its structure through the addition of hydroquinone to the unsaturation of the oil, by electrophilic substitution. It was investigated and confirmed that this reaction is promising for obtaining phenolic products, with high yields (83.5%). The product obtained in this research was evaluated as an antioxidant in commercial biodiesel by the Rancimat method, using 5000 ppm of the synthesized additive the induction period increased from 8 to 17 h (2.12 times). Therefore, this paper brought a positive response to the improvement of biodiesel oxidation stability that creates a possibility to increase the use and expansion of this fuel in the market, as utilization of the safflower seed as raw material for additives, bringing a new market for these seeds.

O parâmetro de solubilidade de poliuretanos segmentados foi determinado através de ensaios de inchamento no equilíbrio, tratando-se os dados pela teoria de Flory-Rehner. O segmento flexível dos poliuretanos foi constituído por blocos de oligobutadieno e o segmento rígido foi formado pela reação entre di-isocianato de tolileno e os extensores de cadeia 1,3-propanodiol; 1,4-butanodiol; 1,6-hexanodiol e 2, 2'-di-hidroxi-isopropil N, N'anilina. O teor em segmento rígido para os polímeros provenientes dos extensores alifáticos ficou na faixa de 25,1% a 28,3%, enquanto que, nos polímeros estendidos com o extensor aromático, foi de 32,6%.

The solubility parameter of a series of segmented polyurethanes was determined through equilibrium swelling experiments, using the Flory-Rehner theory. The soft segment of the polyurethanes was oligobutadiene and the hard block was formed through the reaction of tolylene diisocyanate with propanediol, butanediol, hexanediol or 2, 2' dihydroxy isopropyl N, N' aniline. The hard segment content in all polymers was about the same for the aliphatic extenders (25.1% to 28.3%) and 32.6% for the aromatic one.

Poli(metacrilato de metila) (PMMA) de massa molar controlada foi sintetizado, em solução de tolueno, utilizando peróxido de benzoíla como iniciador e 1-dodecanotiol (DDM) como agente de transferência de cadeia. O efeito da concentração de DDM sobre a massa molar do PMMA foi investigado. Copolímeros de metacrilato de metila e ácido metacrílico, P(MMA-MAA), foram sintetizados a partir da hidrólise parcial de homopolímeros de metacrilato de metila com variadas massas molares. Utilizando uma técnica inédita na literatura para a síntese de ésteres poliméricos, foi realizada a reação das unidades ácidas do P(MMA-MAA) com álcoois de cadeia longa, na presença de 1,3-diciclo-carbodiimida e 4-dimetilamino-piridina, que produziu copolímeros contendo longos segmentos hidrocarbônicos pendentes, tais como o poli(metacrilato de metila-co-metacrilato de hexadecila).

Controlled molecular weight poly(methyl methacrylate) (PMMA) was synthesized in toluene solution using benzoyl peroxide/dodecanethiol as initiator/chain transfer agent system. The effect of the thiol concentration on the molecular weight of PMMA was investigated. Methyl methacrylate and methacrylic acid copolymers, P(MMA-MAA), were prepared by partial hydrolysis of the PMMA homopolymers of different molecular weights. By reacting the acid residues of the copolymers with long chain alcohols, in the presence of 1,3-dicyclohexylcarbodiimide and 4-dimethylaminopyridine, copolymeric esters of PMMA with long chain substituents, such as hexadecyl, were obtained. This technique has not been reported in the literature for the synthesis of PMMA esters.