Effects of Silica Sol on Structure and Properties of Core-Shell Silicon-Acrylic Materials

Xuan Li,Haihua Wang,Yiding Shen,Guiqiang Fei

doi:10.4236/aces.2012.22023

Xuan Li, Haihua Wang + Show 2 more

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https://doi.org/10.4236/aces.2012.22023

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Abstract

Silica sol prepared by sol-gel method was introduced into poly (butyl acrylate) (PBA)/poly (butyl acrylate-styrene-methacryloxypropyl trimethoxysilane) (PSBM) core-shell emulsions to prepare a series of paper surface sizing agents. The rheological measurement indicated that PSBM emulsions exhibited shear-thinning behavior, and the phenomena became more pronounced with increasing silica sol concentration. Dynamic mechanical analysis (DMA) demonstrated that the stronger interfacial interaction between silica sol and polymer matrix, but microphase separation took place with excess silica sol. Thereby the tensile strength and thermal stability of emulsion films were increased with desirable silica sol concentration, and when silica sol concentration was greater than 6 wt%, the tensile strength leveled off and the decomposition temperature decreased from 351.19℃ to 331.63℃. The degree of crystallinity increased from 5.12% to 10.98% with 4% silica sol addition, resulting in enhanced rigidity of films. Furthermore, the interaction between polymer and fiber was improved with certain amount of silica sol, resulting in improved sizing degree, ring crush strength, surface strength and folding strength. However, excessive crosslinking will be harmful for the properties of sized paper.

Highlights

Incorporation of inorganics into organic polymers via covalent bonding has gotten particular attention since the hybrid materials will have a controllable combination of properties of both organic polymers and inorganics [1,2,3,4]
Silica sol prepared by sol-gel method was introduced into poly(butyl acrylate) (PBA)/poly(butyl acrylate-styrenemethacryloxypropyl trimethoxysilane) (PSBM) core-shell emulsions to prepare a series of paper surface sizing agents
The rheological measurement indicated that PSBM emulsions exhibited shear-thinning behavior, and the phenomena became more pronounced with increasing silica sol concentration

Summary

Introduction

Incorporation of inorganics into organic polymers via covalent bonding has gotten particular attention since the hybrid materials will have a controllable combination of properties of both organic polymers and inorganics [1,2,3,4]. Silica/polymer composite materials were prepared by mechanical mixing, molding techniques and sol-gel method. Sol-gel method was one of the most important ways to synthesize hybrid materials composed of polymer and SiO2 owing to its mild processing condition [5,6,7,8,9]. Polymer having functional groups that have specific interactions with silanol groups can prevent the macrophase separation and obtain composites with high homogeneity and optical transparency [9,10,11]. It is reported that mechanical properties and macrophase separation can be improved with increasing hydrophilicity and polarity of polymer matrix [9]. Hybrids obtained from traditional sol-gel synthesis techniques have high volume shrinkage

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