Development of glass fiber/unsaturated polyester-like resins based on modified castor oil

Glass fiber/unsaturated polyester resin composites are one of the most employed materials due to their excellent mechanical properties, room temperature curing and low cost. In this paper, unsaturated polyester-like resins based on modified castor oil were reinforced with glass fiber. The resin consisting of maleated castor oil methacrylate was homopolymerized or alternatively copolymerized with styrene. The effects of glass fiber content on mechanical and dynamic-mechanical properties were evaluated and compared with a commercial unsaturated polyester resin/glass fiber composite. The addition of glass fiber at 20-40 wt% increased flexural properties and impact properties of the composites compared to their neat polymers. At 40 wt% glass fiber, flexural strength and flexural modulus were 235 MPa and 4694 MPa, respectively. These values were near to those obtained for a commercial unsaturated polyester resin with the same fiber load, i.e., 320 MPa and 6843 MPa, respectively. The homopolymer afforded impact strength values of 25-44 kJ/m(2) that were near to commercial unsaturated polyester resin composites (i.e., 20-51 kJ/m(2)), as well. The triglyceride oil provided ductility and impact strength to composites while styrene as comonomer provided stiffness to copolymer composites but decreased their impact strength. A good adhesion was observed between fibers and matrix in copolymer composites in comparison with their homopolymer composites which was enabled through dilution with styrene. [GRAPHICS] .

Automated summary

The study focused on reinforcing unsaturated polyester-like resins based on modified castor oil with glass fiber to improve mechanical properties. Addition of 20-40 wt% glass fiber enhanced flexural properties and impact properties of the composites. Copolymer composites with styrene showed better adhesion between fibers and matrix compared to homopolymer composites.