NC State
Gao, Z., Ma, D., Lv, X., and Wang, Q. (2011). "Formation and evaluation of kraft fibre-reinforced unsaturated polyester (UPE) composites," BioRes. 6(4), 5167-5179.


The effects of moulding pressure and initiator content on the performances of kraft fibre-reinforced UPE composites were investigated by means of tensile evaluation, DMA analysis, SEM analysis, and short-term creep tests. The results indicated that the prepared composites had much higher tensile strength and modulus and better creep resistance than traditional thermoplastic wood plastic composites (WPCs). These improved properties resulted from the incorporation of the strong kraft fibres as reinforcement. The combination of the fibers with the thermosetting UPE matrix produced enhanced kraft-UPE interfacial adhesion. Changes in moulding pressure and initiator level produced various effects in the properties of composites. As the moulding pressure increased from 6 MPa to 25 MPa, the mechanical properties and creep resistances increased gradually until a moulding pressure of 20 MPa was reached; after this point, the values decreased. With an increase in the initiator content from 0.3 PHR (parts per hundred parts of resin) to 1.0 PHR, the tensile strength and interface adhesion first increased, then decreased, while the instantaneous strain and maximum strain values (measured in the creep tests) decreased gradually.
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