Produção de bioplastificantes empregado diferentes catalisadores (enzimáticos e químicos) e aplicação na preparação de filmes poliméricos

Abstract

The main objective of this work was to produce bioplasticizers from vegetable oils such as refined soybean oil (RSO), used soybean cooking oil (USCO) and their derivatives (decyl esters) aimed at preparing poly (vinyl chloride) films. Two main steps were proposed for the present experimental work. In the initial step, was consisted in producing decyl esters via enzymatic esterification of RSO and USCO. The process involved a sequential step of enzymatic oils hydrolysis using crude lipase extract from Candida rugosa (CRL) as catalyst and then the produced FFA was esterified in a solvent-free medium. For such a purpose, lipase from Thermomyces lanuginosus physically adsorbed on rice husk silica particles (TLL-SiO2) was used as heterogeneous biocatalyst and exhibited an immobilized protein concentration of around 28 mg g-1

of support at fixed initial protein loading (40 mg g-1

of support). Complete oils hydrolysis has been achieved after 180 min of reaction and maximum FFA conversion percentage of around 86% has been reached after 90-150 min of reaction. The resulting biocatalyst retained only 10% and 40% of its residual activity after 15 successive esterification batches using FFA from USCO and RSO, respectively. In the second step, different materials having plasticizing properties were produced via epoxidation in situ of vegetable oils (RSO and USCO) and their derivatives (decyl esters) using chemical catalysts (H2O2/formic acid). Epoxidized materials were then used as bioplasticizers to prepare flexible PVC films via a casting process. Resultsindicate that there was a partial conversion of double bonds into oxirane groups of 32.5%-36.4% and 42% for vegetable oils and decyl esters, respectively. The percentage of introduced epoxy groups (IEexp.) was only 2% for all samples tested. On the other hand, their selectivity was around 85%, except for epoxidized USCO (70,1%). PVC films were prepared and those obtained using epoxidized vegetable oils apparently showed greater flexibility and transparency. Moreover, these strategies can be quite promising for producing several bioplasticizers from renewable raw materials (RSO and USCO) through a chemoenzymatic process for further preparation of polymeric films (PVC) of industrial interest.