Cooking schedule of alkyd resin preparation. Part II. Effect of cooking schedule on molecular weight distribution of alkyd resin

Abstract

synopsisThe effect of cooking schedule on the molecular weight distribution of an alkyd resin was investigated. At the molar ratio of 1.03/0.43/1.00 for glycerin, lauric acid, and phthalic anhydride, two kinds of alkyd resin were prepared, one by maintaining the reaction temperature a t 170°C for an hour and then raising it up to 230°C (sample I), the other by raising the temperature up to 230°C a t a uniform rate of 33°C per 10 min. (sample 11). Sample I and sample I1 were fractionated into seven or eight fractions by adding n-heptane to 5 wtr% toluene solution a t 30°C. Acid value, hydroxyl value, intrinsic viscosity [q], and the number-average molecular weight an were determined.The result showed that the molecular weight distribution curve obtained from sample I was much narrower than that from sample 11. In addition, a relation was found between were obtained for sample I and sample 11. Based on the differences in the molecular weight distribution curves and in the rate constants for the esterification reactions, glycerinflauric acid and glycerin/phthalic anhydride at 170' and 23OoC, the mechanism of condensation reaction of short oil alkyd resin was discussed.

Studies in Molecular Weight Determination of Cottonseed and Melon Seed Oils Based Biopolymers

“…It is also evident from Figure 1 and Figure 2 and Table 1 that the number-average molecular weight as well as weight-average molecular weight of the in-process samples decreased with an increase in the oil lengths as also reported in literature for rubber seed oil and castor oil alkyd resins [8] [17]. Nagata [6] suggested that an increase in oil length increases the amount of fatty acid available for reaction, which in turn results in a higher chance of termination of chain growth, resulting in lower molecular weight polymers. The above statement is applicable if fatty acid is used.…”

“…Hence, its properties depend on the average molecular weight and molecular weight distribution. It is well known that the end-use properties of alkyd resin as coatings become optimum at a region along the extent of reaction co-ordinate when appreciable larger molecules begin to form, i.e., cross-linking of molecular chains [5] [6]. Thus, the physical, chemical and mechanical properties of alkyd resins like other polymers are dependent on their relative sizes or molecular weight [5] [7] [8].…”

Formation and Characterization of Paint Based on Alkyd Resin Derivative of Ximenia americana (Wild Olive) Seed Oil

“…The result shows that the extent of reactions at this region varies from 63.33 to 78.57% for samples IV -I. Although these values are relatively lower than the range 75-80% obtained for reaction between phthalic anhydride and glycerol (Nagata, 1969;Carothers 1936), they indicate a significant degree of conversion. However, sample I (78.57%) falls within the range of the reactivity of phthalic anhydride and glycerol, with appreciable degree of conversion consistent with the ideal ratio of 1:2 for XASO: Glycerol for the alcoholysis reaction.…”

Determination of solution viscosity characteristics of rubber seed oil based alkyds resins

“…However, the values are larger in acetone than in toluene for all the samples. It is well known that the value of K is an indication of the homogeneity of the alkyd 14. In other words, the higher the value of K , the more homogenous the alkyd.…”