Pulp cellulose fiber modification by controlled formaldehide grafting by using polyvinylalcohol Crosslink method

Abstract:
Background :formaldehyde was used as a cellulose tissue resistor and important in textiles and is technically feasible. Also in this search, pulp of paper has applied inside to yarn because to more effect elucidation of crosslink reaction.
Objectives: The conditions under which these studies have been made simulate those which have been found useful in the textile industry for the application of formaldehyde and relative Compounds such as polyvinyl alcohol (PVA) was attempted to apply for the improvement of fabrics made of regenerated cellulose fibers.
The main challenge:In usual Formaldehyde is combined with urea to strengthen cellulose tissue But Cellulose- formaldehyde application has two problems. the first problem is hard and brittle of this compound so it is Not suitable for textile industry and second problem is that , gradually compound releases formaldehyde and formaldehyde is smelly and toxic.
Materials and methods: To solve these problems of emission of formaldehid and stiffness , 3 solutions were done In this study, polyvinyl alcohol was used instead of water Borax catalyst was used in the formaldehyde-cellulose reaction and the unreacted formaldehyde was neutralized with solution of sodium hydroxide50%Wt/Wt.
Results:In this study Formaldehyde-cellulose reaction conditions were optimized
, 3 Phenomenons was examined as a goal and proved:
1.Formaldehyde evaporates at 30 ° C without reaction, and at higher temperatures (150 ° C) the reaction of formaldehid-cellulose takes place over a wide range of conditions. But it can be done with borax catalyst at 95oC
2. Reaction is not possible under mildly acidic conditions and the medium must be acidified with HCl or a NH4Clcatalyst must be used.
3. The cellulose-formaldehyde reaction before the addition of urea and the synthesis of cellulose methylene ether reduces the evaporation of formaldehyde. Reducing the evaporation and degradation of formaldehyde makes the product suitable and safe for the textile industry.
4. Treatment of cellulose fibers with formaldehyde in severe acidic conditions causes significant changes in their physical and mechanical properties. The properties of such treatment increase
Improved elasticity and stiffness (Young modulus) in cotton fabric.
In this study, formaldehyde emission (FE) and content (FC) from different types sample; were measured using head-space test method namely Gas Cromarography(GC) and NaHSO4 method. there was no significant effect from the moisture content. approximately the same indication of formaldehyde values, as well as similar behavior, were seen for each method.Moreover, the results indicate surprisingly that there was a good correlation between Values of the emittable formaldehyde concentrations from most of the products investigated . Values of the emittable formaldehyde concentrations from most of the products investigated in the present study were below the limits that are in the usual urea-formaldehid method.
Conclusion:Product of this paper can be use to cellulose coating of soft plastic such as polyvinyl chloride leather and polypropylene yarn. Because it is softer and more elastic than the usual urea-formaldehyde method and releases less formaldehyde.