Effect of molecular weight distribution on viscoelastic properties of polymers

Abstract

Body wash cosmetics are among the most popular and numerous groups of cosmetic products. In chemical terms, they are solutions of surface active agents with the addition of multiple substances such as preservatives, moisturizing agents, fragrances or viscosity modifiers, the aim of which is to improve specific product properties. The present study evaluated the effect of the molecular weight of polyvinylpyrrolidone (PVP) on the properties of face washing products in the form of foam produced with foaming dispensers. A special focus was on key product quality characteristics including foaming properties and skin irritation potential. An addition of PVP to the formulation was found to contribute to an improvement in product foaming properties and a decrease in skin irritation potential. In addition, the studied properties of samples were shown to improve in proportion to the increasing molecular weight of the polymer.

Stress optical measurement of the third normal stress difference in polymer melts under oscillatory shear

“…These results are similar to earlier studies of the linear viscoelasticity of bidisperse polymer melts [14][15][16][17][18][19][20][21]31]. In particular, the ratio of molecular weights used in this study is close to that of sample 41L/435L in the study by Struglinski and Graessley [21].…”

“…The present measurements of the dynamic modulus add to an already extensive body of results on the linear viscoelasticity of bidisperse polymer melts [14][15][16][17][18][19][20][21]. Together these results give experimental evidence supporting a widely predicted constitutive relationship between the normal stresses and the shear stress in oscillatory shear.…”

Influence of molecular weight distribution on the linear viscoelastic properties of polymer blends

“…A number of investigators- 24 have determined experimentally values of qo and/or J," for binary blends of nearly monodisperse polymers of similar chemical structure (e.g., polybutadiene, polyisobutylene, poly(methy1 methacrylate), polystyrene) and attempted to obtain blending laws or to test existing blending laws. In order to facilitate our discussion later, we will review very briefly the highlights of various blending laws proposed in the literature, to the extent that they are relevant to the main idea that we shall expound below.…”

Viscoelastic Properties of Entangled Polymer. IV. Binary Blends of Monodisperse Homopolymers

“…A number of workers invoked some empirical blending rules to obtain the relaxation spectra of mixture s from their constituents (13)(14)(15)(16)(17)(18). However , polymer molecules should behave dif feren tly in a blend than in their pure State because of the interactions with the coexisting components of different chain lengths .…”