High Content Glass Fiber Reinforced Nylon 66 Formulation Design And Optimization

Nylon(PA)is one of the top five engineering plastics with excellent overall performance,and with the growth of demand for "plastic instead of steel" in various countries,PA modified materials with higher performance are emerging.Glass fiber reinforced nylon composites with high glass fiber(GF50,GF60)content have excellent mechanical properties and thermal properties.However,surface defects such as "floating fibers" can appear on the surface of high content glass fiber reinforced nylon composite products.The purpose of this project is to improve the surface properties of the products while maintaining the excellent overall performance of the composites.In this project,different kinds of inorganic fillers,different kinds and contents of nylon resin,different contents of dispersant and flow agent are used to prepare PA66/GF composites by blending with PA66,to study the effects of mechanical properties,melt crystallization properties(DSC),heat deflection temperature(HDT),melt flow rate(MFR),microscopic morphology and apparent properties of the composites,to optimize the test and production formulations.The main findings are the following:(1)The mechanical properties of the composites were reduced after adding different inorganic fillers.From the fracture morphology and sample photos,it can be seen that the addition of calcium carbonate improved the glass fiber dispersion and apparent properties in the composites,and the MFR and HDT were 30.4 g/10 min and 207 ℃,respectively,which were 38% and 16% higher compared with the samples without powder fillers.(2)With the increase of PA6I-6T addition,the mechanical properties of the composites showed a small increase and then decrease,the melting and crystallization peak temperature showed a decreasing trend,and the MFR and HDT showed an increasing and then decreasing trend.The tensile strength,flexural strength,flexural modulus and impact strength of PA6I-6T with 10 wt% addition were 217 MPa,306 MPa,15.2 GPa and 11.2k J/m2,respectively;MFR was 35 g/10min;HDT was 226 ℃;thermal decomposition temperature was greater than 390 ℃;the distribution direction of glass fiber in the resin tended to be the same according to the SEM diagram.And the apparent performance has improved significantly,and there is no "floating fiber" on the surface.(3)Based on the addition of 10 wt% PA6I-6T,the surface of the composite was smooth and free of "floating fibers" when 10 wt% PA6 was added,and the crystallization peak temperature decreased by 31 ℃,MFR increased by about two times,and HDT decreased by12 ℃ when PA6 was not added.When 1～5 wt% PA6 was added,the surface of the composite had a small amount of "floating fiber",and the tensile strength,bending strength and bending modulus were above 200 MPa,290 MPa and 16.5 GPa,with good mechanical properties.decreasing trend.(4)Based on the addition of 10 wt% PA6I-6T,the effect of adding glass fiber dispersant on the DSC properties of the composites was not obvious,and the melt peak temperature was all around 250 ℃ and the crystallization peak temperature was all around 217 ℃.For glass fiber dispersant A,with the increase of content,the MFR of the composites kept rising,and the change of HDT was not obvious,and the apparent morphology of the samples became better,but the mechanical properties decreased significantly,which had limitations on the application of the products.When the content of both dispersants A and B is 0.2 wt%,the dispersion of glass fiber in the resin of the composite is better and the orientation of glass fiber tends to be the same,the MFR is 38.4 g/10 min,the HDT is 224 ℃,the mechanical properties are also at a high level,and there is no obvious "floating fiber" on the surface of the sample,which meets the requirements of industrial production.The mechanical properties are also at a high level.(5)Based on the addition of 10 wt% PA6I-6T,the MFR of the composites increased with the increase of the flow agent content,where the MFR of 40.6 g/10 min was obtained with the addition of 0.6 wt% flow agent,and the apparent properties of the composite samples were significantly improved.(6)The glass fiber reinforced nylon 66 composite material with high glass fiber content prepared in this subject meets the production demand,and the production of 1 ton has been achieved.