Study On The Preparation And Property Of Poss/Pa66Nano-Composite Fibers

Poly hexamethylene adipamide (PA66) has been mainly used in the manufacture of advanced synthetic fiber and tire cord fabric of diagonal tire which has already been manufactured in a considerable scale in China. Nevertheless, catering to the rapid development of economy, the cord with improved dry heat shrinkage, modulus, strength and heat resistance is badly needed by the tire industry. The cage-structured Polyhedral Oligomeric Silsesquioxane (POSS) is a new type of organic-inorganic hybrid materials with merits like:intra-molecular hetero structure, nano-size effect, high heat resistance, improved mechanical properties of polymers, etc. Combining organic phase and inorganic phase with covalent bonds at the molecular level, results in materials with significantly improved performance.This article chose octaphenyl POSS (OP-POSS) and octavinyl POSS (OV-POSS) to reinforce PA66, respectively. The properties of POSS/PA66nano-composite fibers prepared by melt spinning, for example, thermal performance, liquidity, crystallization properties, dry heat shrinkage and mechanical performance, were studied. The results showed that:(1) The initial decomposition temperature raised about10℃with lwt%OP-POSS. With a further increase in OP-POSS content there was no significant change. The molecular mobility of PA66has been improved by OP-POSS which was treated as flow improving agent.(2) The non-isothermal crystallization process of OP-POSS/PA66nano-composite has been successfully explained by Mo Zhishen theory. Cooling rate strongly affected the length of non-isothermal crystallization duration. More specifically, with the increase of the cooling rate, the crystallization rate was accelerated, which resulted in the shortening of the time to reach the crystallization equilibrium value; the crystallization peak shifted to lower temperature and its width widened as well.(3) The grain sizes of phases of γ1,α1and α2of OP-POSS/PA66nano-composite had the tendency to become bigger with the increasing amount of OP-POSS.(4) With1wt%of OP-POSS, the dry heat shrinkage of OP-POSS/PA66nano-composite decreased by16%, compared to pure PA66fibers. In addition, the strength and modulus of OP-POSS/PA66also reached the maximums. But further increasing OP-POSS dosage would result in the reduction of strength and modulus.(5) FTIR and1HNMR are effective methods to characterize the OV-POSS groups. The initial decomposition temperature of OV-POSS/PA66nano-composite raised about8℃with lwt%OV-POSS, which illustrated that the effect of OV-POSS was equivalent to the one with OP-POSS.(6) Compared with pure PA66fibers, the grain sizes of phases of γ1,α1, and α2of OV-POSS/PA66nano-composite was relatively larger. Moreover, the grain sizes of phases of γ1, α1and α2of OV-POSS/PA66nano-composite was obviously enlarging with the increase dosage of OV-POSS, which presented a consistent tendency with OP-POSS/PA66.(7) Compared to pure PA66fibers, the dry heat shrinkage of OV-POSS/PA66nano-composite reduced by24%with1wt%of OV-POSS, which was better than the one with the same dosage of OP-POSS; in addition, the strength and modulus of OV-POSS/PA66also reached their maximums, respectively. What’s more, the amplification of breakage strength of OV-POSS/PA66nano-composite was much greater than the one with1wt%OP-POSS.