Effects Of Nucleating Agent And Surface Structure On Film Properties During Polyolefin Film Processin

Linear low density polyethylene(LLDPE)is widely used in plastic packaging films due to its low cost and good performance,and blown film is currently the most widely used production method in industrial production.Due to the requirements of plastic packaging film application scenarios,the performance of pure LLDPE blown film cannot meet daily needs.In order to obtain better optical properties and mechanical properties,LLDPE needs to be modified.The industrial production process usually adds additives to LLDPE to change Material properties.In this thesis,the influence of the internal crystallization of LLDPE blown films with different contents of nucleating agents and blown films of different stretching rates and the surface topography of LLDPE blown films on optical properties are deeply studied.Blown film internal structure and external surface structure have a huge impact on the performance of the film.In this paper,the internal structure of the film was analyzed by adding different contents of nucleating agent and different pulling rates,and the crystal structure and crystal size of the blown film were analyzed by small angle X-ray diffraction and DSC.Analysis of optical properties of thin films.The surface structure and contact angle of LLDPE blown film were analyzed by optical profilometer and contact angle meter through the external surface structure of several different shed films on the market.The research shows that the addition of nucleating agent leads to the early termination of crystallization of LLDPE film,the decrease of scattering intensity,the increase of crystallization temperature,the enhancement of crystallization ability,and the increase of nucleation sites after the addition of nucleating agent,which leads to the limitation of crystal growth and the change of spherulite size small.In the film blowing process,pure LLDPE blown film has fast stretching speed,high scattering intensity,short crystal growth time,small spherulite size,and orientation-induced crystallization,resulting in increased crystallinity.After adding the nucleating agent,the influence of the stretching rate on the crystal size and crystallinity is reduced,and the spherulite size becomes larger;The droplet performance is better,but the surface relief has an effect on the scattering of light,resulting in increased haze.