Research On The Preparation And Properties Of Polyamide6Composites Reinforced With Nonmetals Recycled From Waste Printed Circuit Boards

In this paper, morphology and main ingredients of nonmetals recycled from wasteprinted circuit boards (N-WPCB) were researched and PA6/N-WPCB composites wereprepared with the N-WPCB powder as reinforced material. Morphological structure andproperties of the PA6/N-WPCB composites were studied, mainly including mechanicalproperties, thermal properties, rheological behavior and crystallization behavior. The maincontents are as follows:（1）Research on morphology and main ingredients of N-WPCB powder:Scanning electron microscope, infrared spectrometer and thermo gravimetric analyzerwere used to analyze the morphology and main ingredients of N-WPCB powder. The resultsshows that the main ingredients of N-WPCB powder are glass fiber, epoxy resin and phenolicresin. The diameter of glass fiber is8μm and the length of glass fiber is in the range of180~360μm.（2）Research on mechanical properties and thermal properties of N-WPCB powder:The research found that the mechanical properties of the composites can be increasedsignificantly by the N-WPCB powder. When the content of the N-WPCB powder is25%, thetensile strength, flexural strength and flexural modulus of the PA6/N-WPCB composites areincreased by33.36%、21.86%and44%respectively, when the N-WPCB powder content is15%, the impact strength of the PA6/N-WPCB composites is increased by9.2%. The dynamicmechanical thermal analysis of the PA6/N-WPCB composites shows that the adding of theN-WPCB powder increased the storage modulus of the composites, but also improve the glasstransition temperature, which can increase the highest using temperature of the composites. Inaddition, the adding of the N-WPCB powder increased the heat distortion temperature of the PA6/N-WPCB composites, when the content of the N-WPCB powder is15%, the maximumincrement is49.6%.（3）Research on rheological behavior of PA6/N-WPCB composites:The study on rheological behavior of N-WPCB powder shows that both PA6andPA6/N-WPCB composites have the properties of pseudoplastic fluid. Non-newtonian indexhas a trend of increasing basicly with the rising of temperature or the content of N-WPCBpowder, which means the non-newtonian decreases. With the increasing of the content ofN-WPCB powder, the apparent viscosity of PA6/N-WPCB composites shows a ascendanttrend and the flow activation energy have a downward trend, which means the composites’sensitivity to the temperature decreases.（4）Research on crystallization behavior of PA6/N-WPCB composites:The study on crystallization behavior of N-WPCB powder shows that there is only asingle γ crystalline form in pure PA6, but the γ crystalline form and α crystalline form arecoexistence after adding the N-WPCB powder. The strong interaction between N-WPCBpowder and PA6and the heterogeneous nucleation effect of N-WPCB powder destroy thespherulite structure of PA6, which made the phenomenon of black cross extinction ofpolarizing microscope photograph become not obvious and the spherulite size becomessmaller and the spherulite quantity become more. The crystalline grain becomes fine, untilvanishing with the increase of the content of N-WPCB powder. The equilibrium melting pointof isothermal crystallization of PA6/N-WPCB composites showed a trend of gradual declinewith the increases of the content of the N-WPCB powder, in addition, the crystallization timebecomes long and the crystallization rate is reduced. The crystallization time ofnon-isothermal crystallization of PA6/N-WPCB composites becomes longer with theincreases of the content of the N-WPCB powder, and the crystallization temperature decreasesand the degree of crystallinity becomes smaller. The classic crystallization kinetics theoryAvrami equation and Mo method can well studied isothermal and non-isothermal kinetics ofcomposites respectively, and the crystallization kinetics parameters of nylon6and itscomposites are obtained by fitting.