The graft copolymerization of starch and methyl acrylate(MA) in three differentreaction systems, MA-CH3OH-H2O, aqueous solution, emulsion system has been carriedout. The composition of the grafted PMA in copolymer and homopolymer PMA, the viscosity-average molecular weight of the graft copolymer, the graft efficiency and freqency and themicrostructure and mechanical property have been investigated. The biodegradable graftplastics with 60% starch was obtained.
This paper shows a calculation model and a method for predicting the tensile strength of the random distributed short fiber composite.On the basis of Renjie Mao's model,the longitudinal tensile strength of the aligned short fiber composite is formulated.Considering the transverse tensile strength and in plane shear strength of the unidirectional fiber composite,and the stress transformation relations of two couples of axes,the stress of the unidirectional fiber composite when it is loaded at an arbitrary angle is obtained.With the aid of an equivalence relation,the calculation formulation of the tensile strength of the random short fiber reinforced composite is deduced.
