Toughening Modification Study Of Polyamide 66 (PA66) At Low Temperature

Polyamide 66 (PA66) is one of the most widely used engineering plastic, which is characterized by high strength, high modulus, high temperature resistance, low shrinkage rate and strong weatherability. It is widely used in the field of automobiles, machinery, electrical appliances, railways and so on. Polyamide 66 has become the indispensable engineering material of the industrial production and processing, partly replacing metal materials. However, at low temperature, PA66 shows strong moisture absorption and low impact strength in its dry state. If used in the cold and dry region, the manufactured products are easy to appear the brittle fracture phenomony at the low temperature. Thus, the toughening modification of PA66 has become a promising subject. To achieve the purpose of toughening modification of PA66 at low temperature, we prepared two kinds of tougher with different grafting rate, one was EPDM-g-MAH, the EPDM that was grafted with MAH, and the other one was POE/EPDM-g-MAH, the mixture of POE and EPDM that was grafted with MAH. Moreover, we studied the effects of the tougher that we prepared on the toughing modification of PA66 material.We prepared two kinds of tougher (EPDM-g-MAH and POE/EPDM-g-MAH) with three different drafting rates, respectively. We characterized the toughter that we prepared with FI-IR, and measured their graft ratios with acid-base titration. The experiment results indicated that all the tougher were grafted successfully, moreover the graft ratio increased and then decreased as the monomer concentration increased. The calculations showed that the graft ratios of the EPDM-g-MAH tougher were 0.46%,0.95%,0.35%(labeled as 1#,2#,3#), respectively, and the graft ratio would get the maximum when the consumption of the MAH was 1.0%-2.0%; the graft ratios of the POE/EPDM-g-MAH tougher were 0.56%,1.15%,0.44%(labeled as 4#,5#, 6#), respectively, and the graft ratio would get the maximum when the consumption of the MAH was 1.0%-2.0%.Firstly, we studied the effects of the EPDM-g-MAH tougher that we prepared on the toughing modification of PA66 material with different dosage. The results indicated:(1) Compared with the commercialized tougher N493, the EPDM-g-MAH tougher we prepared displayed much more better performance at low temperature, implying that EPDM effectively improved the low temperature performance of PA66, however, slight worse at room temperature; (2) In general, the impact strength and elongation at break were positively correlated with the graft ratio of tougher. Moreover,the tougher 2# had the biggest graft ratio among the three EPDM-g-MAH tougher. So, compared with the tougher 2# and 3#, the tougher 2# exhibited the best performance no matter at low temperature or room temperature; (3) As the consumption increasing, the effect of the tougher 2# on the toughing modification of PA66 improved, and the speed of the improvement became slow when the content of the tougher 2# was more than 12%. Therefore, we considered that the optimum addition of the tougher 2# is 12%.In order to improve the effects of the EPDM-g-MAH tougher on the toughing modification of PA66 at room temperature, we prepared POE/EPDM-g-MAH tougher with three different graft ratios, and studied their toughing modifying effects on PA66 materials. The analysis results indicated that:(1) Compared with the commercialized tougher N493, the POE/EPDM-g-MAH tougher we prepared displayed much more better performance at low temperature; (2) At room temperature, compared with the EPDM-g-MAH tougher that we prepared, the effects of the POE/EPDM-g-MAH tougher on the toughing modification of PA66 improved obviously, and were close to the effect of N493, implying that the addition of POE greatly improved the performance of PA66 at room temperature; (3) Compared with the tougher 4# and 6#, the tougher 5# exhibited the best performance no matter at low temperature or room temperature, the main reason was its high graft ratio; (4) Under comprehensive analysis, we considered that,for the toughing modification of PA66, the best tougher was the POE/EPDM-g-MAH tougher 5#, and its optimum addition is 12%.