| Nylon66is a kind of widely used engineering plastic. For its high crystalline, excellent mechanical properties, outstanding low temperature performance and stabilized chemical properties, it has been widely used in automotive, electronic, chemical, mechanical, instrumentation construction industry and so on. Introducing with the glass fiber into not only improving the mechanical properties of Nylon66but also giving some other novel performances to it, with the development economy technology and the improvement of many fields for material, nylon66/glass fiber composites have being broad application prospect and interested by more and more.In this paper, the nylon66/glass fiber composites were prepared by melt blending with the nylon66and the glass fiber after surface treated. The mechanical properties, dynamic mechanical properties, thermal properties (thermal stability performance, thermal expansion performance, melt crystallization behavior), corrosive chemical resistance of composites and dispersibility of glass fibers in composite as well as in the length distribution in the composite were investigated. The main research contents and the results are as follows:(1) The compatibility of glass fiber and nylon66was improved after the compatible group was grafted with silane coupling agent KH550on glass fiber. The glass fiber length in the composites decreased from612.8μm to526.7μm with the content of the glass fiber increasing.(2) The rigidity and toughness of composites significantly were improved by glass fiber significantly. When PA66content was40%, the tensile strength and bending strength of composites were greatly increased even up to173%and186%, respectively. Impact strength has also been significantly improved, and increase was283%. When TAF content was0.8%, the mechanical properties of composites whose glass fiber content was25%were excellent. It can be seen from the SEM images that the glass fibers embedded in the nylon66matrix, and the root close bonded with nylon66. Abundant of resin attached on the surface of the exposed glass fiber was observed.(3) DMA analysis revealed that an observable enhance effect of glass fiber on nylon66. Storage modulus of nylon66/glass fiber composites increased. When the glass content was40%, the E’of composites increased by305%compared with pure nylon66. Linear increase relationship between storage modulus and glass fiber content was observed. And the a main transition peak shifted to high temperature about17℃.(4) TG test results showed that the thermal stability of nylon66was improved significantly with addition of glass fiber. Compared with pure PA66, the Tdi of composites improved by7～30℃; Td improved by20～50℃. Meanwhile the coefficients of thermal expansion (CTE) of composites reduced and the dimensional stability was improved. As the contents of glass fiber increasing, the CTE of composites decreased at most74.2%. The CTE of composites increased firstly, then decreased to an equilibrium level with the temperature increasing, and the discontinuity temperature appeared near37℃.(5) The corrosion of pure nylon66was the most serious in10%hydrochloric acid. With the extension of immersion, after a week its tensile strength and flexural strength decreased by55.6%and79.8%, respectively. Glass fiber slow down the corrosion of nylon66, after a week the tensile strength and flexural strength decreased by32.0%and51.4%, respectively. Then was in10%aqueous sodium hydroxide solution. Furthermore was ethylene glycol. The glass fiber prevented the alcoholysis of nylon66.120#solvent oil had a little influence on the mechanical properties of composites. Glass fiber significantly reduced the acid hydrolysis, alkaline hydrolysis and alcoholysis of composites, and it improved the retention rate of mechanical properties of composites to some extent. |
PDF Full Text Request