A series of the copolymers of ethylene with 1-hexene （M1-M9） synthesized by metallocene catalyst Et[Ind]2ZrC1JMAO was studied by differential scanning calorimetry and successive self-nucleation and annealing （SSA）...A series of the copolymers of ethylene with 1-hexene （M1-M9） synthesized by metallocene catalyst Et[Ind]2ZrC1JMAO was studied by differential scanning calorimetry and successive self-nucleation and annealing （SSA） thermal fractionation. The distribution of methylene sequence length （MSL） in the different copolymers was determined using the SSA method. The comonomer contents of samples M4 and M5 are 2.04 mol% and 2.78 mol%, respectively. Both M4 and M5 have low comonomer content and their MSL distribution profiles exhibit a monotonous increase trend with their MSL. The longest MSL of M5 is 167, and its corresponding molar percent is 43.95%, which is higher than that of M4. Moreover, the melting temperature （Tm） of M5 is also higher than that of M4. The comonomer contents of samples M7, M8, and M9 are 8.73 mol%, 14.18 mol% and 15.05 mol%, respectively. M7, M8, and M9 have high comonomer contents, and their MSL distribution profiles display unimodality. M7 has a lower peak value of 33 and a narrow MSL distribution, resulting in a Tm lower than that of M8 and M9. The MSL and its distribution are also key points that influence the melting behavior of copolymers. Sometimes, MSL and its distribution of copolymers have a greater impact on it than the total comonomer contents, which is different from traditional views.展开更多
The stereo-defects distribution of polypropylene of the two industry biaxially oriented polypropylene （BOPP） samples T28FE and F28SO with different processing properties was studied through successive self-nucleatio...The stereo-defects distribution of polypropylene of the two industry biaxially oriented polypropylene （BOPP） samples T28FE and F28SO with different processing properties was studied through successive self-nucleation and annealing （SSA） technique. It was found that there were more medium isotactic components in sample F28SO, and the isotactic sequence length of polypropylene of sample F28SO was shorter and the isotactic sequence length distribution of polypropylene of sample F28SO was broader, which could be processed well at high-speed orientation during the processing of BOPP films. This result indicates that the isotactic sequence length distribution of polypropylene is related to the processing speed during preparing BOPP films, and the stereo-defects distribution of polypropylene has an important influence on its processing ability.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.20734006 and 50921062)
文摘A series of the copolymers of ethylene with 1-hexene （M1-M9） synthesized by metallocene catalyst Et[Ind]2ZrC1JMAO was studied by differential scanning calorimetry and successive self-nucleation and annealing （SSA） thermal fractionation. The distribution of methylene sequence length （MSL） in the different copolymers was determined using the SSA method. The comonomer contents of samples M4 and M5 are 2.04 mol% and 2.78 mol%, respectively. Both M4 and M5 have low comonomer content and their MSL distribution profiles exhibit a monotonous increase trend with their MSL. The longest MSL of M5 is 167, and its corresponding molar percent is 43.95%, which is higher than that of M4. Moreover, the melting temperature （Tm） of M5 is also higher than that of M4. The comonomer contents of samples M7, M8, and M9 are 8.73 mol%, 14.18 mol% and 15.05 mol%, respectively. M7, M8, and M9 have high comonomer contents, and their MSL distribution profiles display unimodality. M7 has a lower peak value of 33 and a narrow MSL distribution, resulting in a Tm lower than that of M8 and M9. The MSL and its distribution are also key points that influence the melting behavior of copolymers. Sometimes, MSL and its distribution of copolymers have a greater impact on it than the total comonomer contents, which is different from traditional views.
基金financially supported by the National Natural Science Foundation of China(No.51073170)
文摘The stereo-defects distribution of polypropylene of the two industry biaxially oriented polypropylene （BOPP） samples T28FE and F28SO with different processing properties was studied through successive self-nucleation and annealing （SSA） technique. It was found that there were more medium isotactic components in sample F28SO, and the isotactic sequence length of polypropylene of sample F28SO was shorter and the isotactic sequence length distribution of polypropylene of sample F28SO was broader, which could be processed well at high-speed orientation during the processing of BOPP films. This result indicates that the isotactic sequence length distribution of polypropylene is related to the processing speed during preparing BOPP films, and the stereo-defects distribution of polypropylene has an important influence on its processing ability.
