Rheological and Dynamic Light Scattering Behavior of PVC/plasticizer Solutions

• Main Authors: SU, YU-MIN, 蘇郁閔
• Other Authors: Mao, Ching-Feng
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/hdys85

碩士 === 南臺科技大學 === 化學工程與材枓工程系 === 105 === PVC Plastisols are a mixture of PVC particles and plasticizers, which exhibits excellent flowability and processability. On heating, the PVC particles of PVC plastisols tend to disperse in plasticizers and form 3D network with high elasticity (called flexible PVC) after cooling. The aim of this study is to investigate the effect of different plasticizer on PVC/plasticizer mixtures after heating. The properties of the PVC/plasticizer mixtures were characterized by the rheological and the dynamic light scattering methods. The frequency-sweep rheological measurement of the PVC/ plasticizer samples showed that at low concentrations, the loss modulus curve has a slope close to 2 and has a value higher than the storage modulus, exhibiting the nature of liquids; at high concentrations, the storage modulus is greater than the loss modulus and independent of frequency, showing the features of gels. The light intensity distribution as a function of sampling time shows a Gaussian distribution for liquid samples; in contrast, a non-Gaussian distribution was observed for gel samples. The time-intensity correlation function of the liquid samples has a value similar to the default  value and a high X value obtained from the heterodyne approach. For gel samples, the  and X values are extraordinarily low. The perturbation part of the time-intensity correlation function can be extracted by using the heterodyne approach, followed by the relaxation rate analysis. The results showed that in the liquid state, the particle size of the PVC/DOP samples is greater than that of others due to the high compatibility between PVC and DOP, which enhances the swelling the PVC particles during heating, thus leading to large particles as well as the aggregation of PVC particles.