A series of long glass fiber reinforced polystyrene composites with different contents of compatibilizer were prepared by using a self-designed impregnation device. The matrix resin is polystyrene

the compatibilizer is polystyrene grafted maleic anhydride

and the toughening agent is a thermoplastic polyurethane elastomer. Effects of compatibilizer content on performance of long glass fiber reinforced polystyrene composites were studied. The results demonstrates that the storage modulus of long glass fiber reinforced polystyrene composites first increases and then decreases with increasing compatibilizer content

which predicts that the mechanical properties of long glass fiber reinforced polystyrene composites first increase and then decrease with increasing compatibilizer content; the tan values of long glass fiber reinforced polystyrene composites first decrease and then increase with increasing compatibilizer content

which demonstrates that the compatibility of the composites first increases and then decreases with increasing compatibilizer content; SEM results demonstrated that glass fibers were coated by the matrix resins

when the compatibilizer was added into the composites

and the compatibility mechanism was analyzed.