The crystallization behavior of two commercial polyolefin elastomer(POE)samples was investigated using the fast scanning chip calorimetry(FSC)technique.Non-isothermal crystallization of the POE samples during cooling ...The crystallization behavior of two commercial polyolefin elastomer(POE)samples was investigated using the fast scanning chip calorimetry(FSC)technique.Non-isothermal crystallization of the POE samples during cooling to low temperatures cannot be inhibited under the largest efficient cooling rate employed in the current work.Thus,the isothermal crystallization of POE samples was limited to a narrow temperature range.When the POE samples were cooled to a certain temperature below the non-isothermal crystallization temperature for crystallization,a crystallization time dependent melting peak appeared in the low temperature region besides the high temperature melting peak originated from the non-isothermal crystallization.This low temperature melting peak was arisen from the melting of crystals isothermally crystallized at the selected crystallization temperature.At each crystallization temperature,the lengths of crystallizable segments were different,thus,the low melting peak increased with increasing the crystallization temperature.In terms of the high melting peak attributed to the non-isothermally crystallized crystals,it somehow decreased with increasing crystallization time and then became constant with further increasing crystallization time at the selected crystallization temperature.This could be explained by the fact that the crystallizable sequences with longer length would nucleate and crystallize first to form thicker crystals during cooling.The subsequent crystallization contributed by the shorter crystallizable sequences will result in the formation of thinner crystals,causing the melting peak to shift to the lower temperature.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52422301)Natural Science Foundation of Jilin Province(No.SKL202302033)。
文摘The crystallization behavior of two commercial polyolefin elastomer(POE)samples was investigated using the fast scanning chip calorimetry(FSC)technique.Non-isothermal crystallization of the POE samples during cooling to low temperatures cannot be inhibited under the largest efficient cooling rate employed in the current work.Thus,the isothermal crystallization of POE samples was limited to a narrow temperature range.When the POE samples were cooled to a certain temperature below the non-isothermal crystallization temperature for crystallization,a crystallization time dependent melting peak appeared in the low temperature region besides the high temperature melting peak originated from the non-isothermal crystallization.This low temperature melting peak was arisen from the melting of crystals isothermally crystallized at the selected crystallization temperature.At each crystallization temperature,the lengths of crystallizable segments were different,thus,the low melting peak increased with increasing the crystallization temperature.In terms of the high melting peak attributed to the non-isothermally crystallized crystals,it somehow decreased with increasing crystallization time and then became constant with further increasing crystallization time at the selected crystallization temperature.This could be explained by the fact that the crystallizable sequences with longer length would nucleate and crystallize first to form thicker crystals during cooling.The subsequent crystallization contributed by the shorter crystallizable sequences will result in the formation of thinner crystals,causing the melting peak to shift to the lower temperature.
