Study On Microscopic Structure And Thermal Stability Of Garment Leather

The thermal stability of natural leather is an important factor in the wear performance. In the early stage of literature searching, we found that, at present much of the research about this property are based on macroscopical experiment method, there is only a bit of microscopic analysis of leather thermal stability. In this study, through the method of molecular dynamics simulations, we understand the internal structure of type I collagen molecules furthermore, which is the main type protein molecules of natural leather. This research through establishing molecular models of natural leather and analysising conformation of the simulated trajectories to identify the relationship between the thermal stability of natural leather and the internal space conformation.We first download ID for 1CGD of type I collagen from protein database, which is the basic matreial of natural leather. Then using molecual dynamics simulation method through the AMBER11 software to 1CGD in AMBER ff99 SB force field and free boundary conditions, Third, using the canonical ensemble, and time step of 1 fly seconds, for molecular dynamics simulation with 1 ns respectively in 298 K, 338 K, 378 K and 418 K. Finally we successful established 1 CGD type I collagen molecular model at different temperatures.At last we analyze the simulated trajectories under different temperatures by these three parameters, the root mean square deviation, radius of gyration and contact number, as well as the trajectories at different moments intercepted by the VMD software. The results of type I collagen conformation as the temperature changes contain four aspects. First,with the temperature from 298 K to 418 K, type I collagen space conformation deviates from the natural conformation increasely, the molecular structure becomes curved,and the group at the end of the molecular chain become separated. The Rg of the 1cgd from 25.9 to 24? with the temperature rised from 298 K to 418 K. It means that I collagen protein structure becomes more closely as the temperature rise. Under the condition 298 K to 418 K,the contact number from 780 to 690, which means that structural stability of the protein molecule decreases as the temperature increases.