Study of Cross-Linking between Boric Acid and Different Types of Polyvinyl Alcohol Adhesive

Ravindra V Gadhave,Pradeep T Gadekar,Prakash A Mahanwar

doi:10.4236/ojpchem.2019.91002

Abstract

Polyvinyl alcohol (PVA) is water-soluble polymer manufactured by the saponification of polyvinyl acetate. The physical properties and its specific application depend on the degree of hydrolysis. To enhance the properties of different hydrolyzed PVA grades, it is generally chemically modified with various cross-linkers. Here, different degree hydrolyzed PVA grades with enhanced properties were achieved by cross-linking with boric acid. These samples were then characterized by Differential Scanning Calorimetry (DSC) and Gel permeation chromatography (GPC). For further analysis a film of samples were prepared by casting on glass plate. The effects of amount of boric acid and degree of hydrolysis of PVA on performance properties like tensile strength, pencil hardness and thermal properties like glass transition temperature were studied. The results showed that by cross-linking there was an increase in mechanical strength and thermal property.

Highlights

Polyvinyl alcohol (PVA) is one of the most important commercial water soluble polymers
The M PVA has the lowest viscosity due to very less H-bonding, caused due to modification of PVA. 2) Glass transition temperature (Tg) There is an increase in Tg after cross-linking it with boric acid as seen from Table 3
While comparing the increase of PH PVA with FH PVA, it is seen that the PH PVA has the greater molecular weight as compared to FH PVA, this can be attributed to the better cross-linking in PH PVA, as the chains are not that tightly spaced the boric acid can attack the hydroxyl groups of PH PVA

Summary

Introduction

Polyvinyl alcohol (PVA) is one of the most important commercial water soluble polymers. It possesses high crystalline structure [1]-[6]. It has excellent gas barrier properties, high strength, and flexibility. The cross-linking helps to improve the mechanical properties and water stability of PVA based products. Since the PVA and starch are rich in hydroxyl groups, boric acid can be expected to cross-link with them and further improve the adhesion [15]. Different hydrolyzed PVA is cross-linked in water solution with boric acid as a cross-linking agent to observe the effects on physical, mechanical and thermal properties of PVA solutions

Experimental

Characterization and Testing

Results and Discussion

Conclusion