Raquel S. Mauler

A styrene–butadiene–styrene triblock copolymer (SBS) was functionalized with glycidyl methacrylate (GMA). Grafting reactions were carried out in an internal mixer at 170°C, using dicumyl peroxide (DCP) as an initiator. The effect of three variables, % GMA, % DCP, and reaction time, on grafting were studied using a factorial design to analyze the experimental data. GMA was grafted onto SBS and its incorporation increased with the % GMA added. The factors levels studied indicated that was an optimum % DCP point about 0.1% w/w to achieve the best incorporation and conversion values. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2074–2079, 2003

Silicone masterbatch (SMB) is a pelletized formulation containing 50% of an ultrahigh molecular‐weight polydimethylsiloxane dispersed in polyethylene. This SMB is designed to be used as an additive in polyethylene‐compatible systems to impart benefits such as processing improvement and modification of surface characteristics. In this work, binary blends of high‐density polyethylene (HDPE) and SMB were prepared by melt‐mixing technique to study the influence of this masterbatch on the processing and mechanical properties of HDPE. Ternary blends were also prepared by the addition of silane‐grafted polyethylene (HDPE‐VTES) as compatibilizer. The blends were analyzed by melting flow rate (MFR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and tensile tests. Data of final torque and MFR showed that SMB improved the processability of pure HDPE. DSC results showed differences in crystalline behavior between binary and ternary blends. In the former, the degree of crystallinity increased up to 10 wt % of SMB content; beyond this concentration, it decreased. In ternary blends, a reverse behavior was observed. The morphologic study showed silicone particles uniformly distributed in HDPE matrix. With high SMB concentration, the addition of HDPE‐VTES significantly reduced the size of silicone particles. In the range of SMB composition studied, the mechanical properties of blends lower slightly compared to pure HDPE. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2347–2354, 2002

Polyamide and polypropylene (PP) are two important classes of commercial polymers; however, their direct mixing leads to incompatible blends with poor properties. Polypropylene functionalized with glycidyl methacrylate (PP‐GMA) was used as a compatibilizer in blends of PP and nylon 6, because of the possible reaction of NH₂ and COOH groups with the epoxide group of GMA. Two types of nylon 6 with different ratios between NH₂ and COOH groups were used. The one with higher concentration of COOH groups was less compatible with PP in a binary blend. When PP‐GMA was used as a compatibilizer, a better dispersion of nylon in the PP matrix was obtained together with better mechanical properties for both nylons used in this work.© 2001 Society of Chemical Industry

RESUMO: Polipropileno (PP) foi funcionalizado com viniltrietoxisilano (VTES) em solução e no estado fundido, utilizando peróxidos como iniciadores. A influência da concentração de silano e de peróxido sobre o grau de funcionalização foi avaliada por Espectrometria no Infravermelho com Transformada de Fourier (FTIR). As reações feitas no estado fundido resultaram em produtos com maior grau de funcionalização. Medidas de torque e determinações de peso molecular por Cromatografia de Permeação em Gel (GPC) demonstraram a ocorrência de reações de quebra de cadeia em todos os sistemas, porém mais acentuadamente nas reações feitas no estado fundido.