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The sensitivity of the flow stress of polymers to strain-rate is one of the major concerns in mechanics of materials since polymers and polymer matrix composites are widely used in many engineering applications. In this paper, we present tests on Nylon 6 and Nylon 66 on wide range of strain-rates (0.001-5000s⁻¹). Specifically, we used INSTRON machine for low strain-rates. The high strain-rate measurements were inferred from the Hopkinson bar tests. Only the compressive behaviour was investigated. To eliminate any interference with temperature and humidity effects, test samples were conditioned at 20°C and 50% of hygrometry. Moreover, the effects of the specimen geometry were considered. The current study results are also compared to values found in literature.

In this research, a series of amorphous nylons 6 were prepared by introducing adipic acid and different structure amines into the copolymerization with caprolactam. The effects including thermal properties, crystallinity, dynamic mechanical properties, optical properties, and water absorption of different copolymerization structure and copolymerization ratio on the properties of nylon 6 were investigated. The results show the melting point and thermal cracking temperature Td 5 of nylon 6 are, respectively, between 179${}^{\circ }$C and 217${}^{\circ }$C and 278${}^{\circ }$C to 336${}^{\circ }$C. Nylon 6 structure introducing a methyl side chain is more effective than a meta-benzene ring, a meta-cycloalkyl, and bicycloalkyl groups, so CAMM and CAI have the lowest crystallinity.

The preparation process-dependent phase morphology of blends composed of nylon 6 and acrylonitrile-butadiene-styrene (ABS) over a composition range of 30-70 wt% using a styrene-maleic anhydride (SMA) copolymer as the compatibilizing agent with a constant content (5phr) was investigated. The results of the scanning electron microscope (SEM) observation revealed that compared with the binary blends of nylon 6 and ABS, the existence of SMA caused a composition shift of phase inversion to a higher weight fraction of nylon 6 when ABS was blended with the preblended nylon 6/SMA blend, while the co-continuous structures could be observed over a considerably narrower composition range when nylon 6 was blended with the pre-blended ABS/SMA blend. An examination through dynamic mechanical analysis (DMA) tests confirmed the results obtained with SEM. It is found that near the phase inversion region a remarkable change in the dynamic storage modulus (G′) and the loss tangent (tanδ) appears. Moreover, the influence of blending sequence on the size of dispersed particles has been probed for uncompatibilized and compatibilized blends of nylon 6 and ABS over a wide range of compositions below or beyond the phase inversion points. For the blends of ABS dispersed in a nylon 6 matrix, little discernible effects of blending sequence on particle size could be observed. Furthermore, there exists a significant difference in morphologies of the blends prepared by nylon 6 particles dispersing in a ABS matrix in cases of different blending sequences used. Some possible factors responsible for the above asymmetric behaviors have been proposed.