Reducing the print-through phenomenon and increasing the curing degree of UP/ST/organo-montmorillonite nanocomposites

Abstract Recently, the vacuum-injection method was considered the best approach for making the hulls of yachts. However, the resins show a print-through phenomenon (PTP) on the yacht surface when using unsaturated polyester resins (UP)/glass fiber and vinyl ester (VE)/glass fiber composites. The reason is the different degrees of curing within the UP or VE resin which leads to different thermal contractions of the composite. When the copolymer is prepared by the free-radical polymerization reactions of UP/ST, the variation in volume shrinkage is about 7–10%, thereby causing twists and wrinkles on the surface. To reduce these problems, organo-montmorillonite was added as filler to improve the dimension stability of the UP/ST/LPA matrix. Styrene (ST) is a bifunctional material, acting as a solvent and as a crossing agent in UP. LPA is a low-profile additive, which is applied for dimensional stability to improve the shrinkage. Flame-resistant improvement was also tested after adding organo-montmorillonite. Wide-angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM) techniques were applied to explain the morphology of the UP/ST/organo-montmorillonite nanocomposites. The volume shrinkage of the resin was determined by density measurements.