The effect of fiber content on mechanical properties of carbon fiber reinforced thermoplastic composites

U radu su ispitana mehanička svojstva kompozita s plastomernom matricom od kopolimera etilena i metil metakrilatne kiseline ojačanog ugljičnim vlaknima. Izrađene su dvije kompozitne ploče, svaka s dva sloja jednoosno orijentiranih vlakana pri jednakim uvjetima proizvodnje. Ispitna tijela izrezana su paralelno, te su ispitana svojstva prividne smične međuslojne čvrstoće, savojnog modula elastičnosti i savojne čvrstoće. Dobivene vrijednosti ukazuju na ponovljivost kvalitete izrade ploče. Svojstva ploče s dva sloja vlakana uspoređena su sa svojstvima ploče sa samo jednim slojem. Savojni modul je porastao za red veličine, a prividna smična međuslojna čvrstoća za 14,6 %. Zbog vrlo male krutosti ploče s jednim slojem vlakana, nije bilo moguće odrediti čvrstoću pri savojnom opterećenju.The mechanical properties of a composite with a thermoplastic matrix made of copolymers of ethylene and methyl methacrylic acid reinforced with carbon fibers were investigated. Two composite sheets were made, each of them was reinforced with two layers of uniaxially oriented fibers under the same manufacturing conditions. The values obtained indicate the reproducibility of the sheet quality. The properties of the sheet reinforced with the two layers were compared with those uniaxially reinforced with a single layer. The flexural modulus increased by an order of magnitude and the apparent shear interlayer strength by 14,6 %. Due to the very low stiffness of the single-layer sheet, it was not possible to determine its flexural strength Key words: thermoplastic based composites, uniaxial reinforcement, apparent interlaminar strength, flexural modulus, flexural strength