Study On Characterization Of Polymer Plasticization Law In Calendering Process By Color Test

Calendering is an important process in polymer processing,and its main function is plasticizing.The quality of polymer calendering and plasticizing is directly related to the final product.Plasticizing degree directly reflects the plasticizing quality of polymer.The higher the plasticizing degree,the better the plasticizing quality.In this paper,offline and online color testing methods and traditional SEM,mechanical properties,density,DSC and melt flow rate methods are used to study the relationship between color change and plasticization degree during calendering of PVC system,PVC/NBR system and energetic material substitute system.The main conclusions are as follows:(1)Using off-line color test method and traditional plasticizing degree characterization method,it is concluded that when standard color differenceΔE0 is close to 0 and hunter whiteness W2 reaches the maximum,PVC system and PVC/NBR system have the common characteristics of dense material,good mechanical properties and high viscosity,and the plasticizing degree is the best at this time;When the standard color difference ΔE0 is close to 0 and the weighting factor E*tends to be stable,the plasticization degree is the best.The results show that the plasticization degree can be characterized by the above color parameters,which shows that the color method is reasonable to characterize the calendering plasticization of polymer.(2)On-line color testing method based on micro-optical fiber spectrometer combined with traditional characterization of plasticizing degree,the relationship between real-time dynamic color change and plasticizing degree of different materials in calendering process was studied.The results showed that for PVC system and PVC/NBR system,the plasticizing degree was best when the standard color difference ΔE0 tended to 0,the real-time color difference ΔEij and Hunter whiteness W2 fluctuated little and stabilized.For the substitute system of energetic materials,the real-time color differenceΔEij,Hunter whiteness W2 and weighting factor E*tend to be stable when the fluctuation is small,and the plasticization degree is the best when the standard color difference ΔE0 is close to 0 and the L*value tends to be stable.Therefore,the above color parameters can be used to characterize the plasticization degree of polymers,which further shows that the color method is reasonable.(3)By changing the formula and process parameters,the relationship between color change and plasticization degree of PVC system and substitute system was studied.The results showed that when the formula and process parameters(roller temperature,gap between two rollers)changed,there was always a small fluctuation of real-time chromatic aberration ΔEij which tended to be stable,and the mechanical properties were good,the viscosity was high,and the plasticization degree was the best.It is proved that the color method is feasible to characterize the degree of plasticization of polymer calendering.(4)By changing the color test parameters,the online color test results of PVC system and substitute system are studied.It is concluded that changing the color test parameters will have a great impact on the color test results of materials,but they all have the best color test parameters to characterize their plasticization degree.Through the experiments of different materials in different formulas,process parameters and on-line color test parameters,it is concluded that it is completely feasible to use color method to characterize the degree of polymer calendering and plasticization,and it is expected to be widely used in industry.