| Polyamide 1010 as the representative of long-chain polyamides are widely used in automotive,military equipment and other fields that has advantages in its excellent properties,such as good comprehensive mechanical performance,dimensional stability,resistant chemical reagents,etc.In recent years,researches on polyamide 1010 focused mainly on the condensed matter structure,mechanical properties,compound modification and other aspects.However,the study on the dynamic structure,properties under the annealing process and the simultaneous thermal drawing of polyamide 1010 is still insufficient.It is useful for us to establish links among structure,processing molding and property,and provide the theoretical basis for the actual production at the same time,if the structure variation of polyamide 1010 as well as the relationship between tensile temperature and draw ratios under the condition of annealing and simultaneous thermal drawing could be fully mastered.Accordingly,the annealing and synchronous thermal drawing of polyamide 1010 will be studied in this paper.Polyamide 1010 samples with different crystal forms were prepared by constant melt-cooling and melt-quenching.The dynamic structure was studied by wide angle X-ray diffractometer(WAXD)equipped with a hot tensile stage.The polyamide 1010 with different crystal forms was annealed at RT(room temperature,25°C),100°C,110°C,120°C,130°C and 140°C,respectively.Then synchronous thermal draw the polyamide 1010 with a constant draw rate of 10 μm/s,the draw ratios were 1.00、1.25、1.50、1.75、2.00、2.25、2.50 and 3.00 times,respectively.The dynamic transition of structure and the changes of tensile force was observed under different annealing temperature and the draw ratios.The orientation at different drawing ratios was also observed on 2D WAXD graphs.Through the researches,we get the following conclusions:(1)The α-crystal structure of polyamide 1010 was obtained by constant melt-cooled,which could be presented stably at room temperature.Annealing at 100℃-140 ℃was showed a promotion on the Brill transition and crystallization of the α-crystal structure of polyamide 1010.The higher the annealing temperature,the more obvious the transition and the greater the crystallinity.(2)Synchronous thermal drawing of the polyamide 1010 with the α-crystal could promote it undergo Brill transition and induce further crystallization.The Brill transition occurred when constant melt-cooling polyamide 1010 was synchronous thermal drawn under the annealing temperature 100℃-140℃.The bigger the draw ratios,the more obvious the transition.And the Brill transition was finished when the draw ratio was 2.50 times,in which ratio the α-crystal structure was fully transformed into γ-crystal.With the increase of the draw ratios,the crystallinity increased first,but then decreased,and the crystallinity reached the maximum when it was drawn to 2.25 times.The degree of orientation also increased,but it basically remained unchanged when it was drawn to 2.50 times.The tensile force increased gradually,too.The tensile force has a stronger ability than temperature to induce the polyamide 1010 undergo the Brill transition.(3)The γ-crystal structure of polyamide 1010 was obtained by melt-quenching.When it was annealed at the 100℃-140℃,the crystal structure has not been changed.And the γ-crystal also was presented at high temperatures,but the stability was poorer than at room temperature.The temperature could promote crystallization and produce a trace of α-crystal structure.As the annealed temperature increasing,the crystallinity also increased.(4)Synchronous thermal drawing of the polyamide 1010 with the γ-crystal does not promote it to take place Brill transition,however,it could induced crystallization and form the α-crystal.When the melt-quenching polyamide 1010 was synchronous thermal drawn at the 25 and 100℃ ℃-140℃,with the increase of the drawing ratios,the crystallinity increased first,but then decreased,and the crystallinity reached the maximum when it was drawn to 2.00 times.When the drawing ratios was less than 2.00 times,the tensile force mainly induced crystallization,and after 2.00 times,the tensile force mainly destroyed the crystallization.With the increase of the drawing ratios,the degree of orientation also increased,but it basically remained unchanged when it was drawn to 2.50 times.And the tensile force increased gradually,too.(5)Synchronous thermal drawing induced crystallization of polyamide 1010,at same drawing ratios,the degree of crystallinity of the polyamide 1010 with α-crystal was increased more than the polyamide 1010 with γ-crystal.In the synchronous thermal drawing process,the polyamide 1010 with γ-crystal was more easily to be oriented,but the degree of orientation of the polyamide 1010 with α-crystal was larger than the polyamide 1010 with γ-crystal when drawn at same ratios and occurred orientation.The polyamide 1010 with γ-crystal required less tensile force when it was synchronous thermal drawn with the same ratios,the variation of the(002)crystal plane d-spacing mainly depended on the drawing ratios. |
