Heats of fusion, melting transitions, and the derived entropies of fusion were obtained by differential scanning calorimetry for examples from three homologous series of homopolymers having long side chains. Homopolymers having side‐chain lengths between 12 and 22 carbon atoms were chosen from the poly(n‐alkyl acrylates), the poly(N‐n‐alkyl‐acrylamides) and the poly(vinyl esters). The data demonstrated that only the outer paraffinic methylene groups were present in the crystal lattice. This was concluded because phase diagrams obtained for mixtures of structurally different monomers and homopolymers, as well as for selected copolymers, showed only isomorphism in the polymeric examples. In addition, scanning curves, reflecting the distribution of crystallite sizes, became narrower as the side chains became longer. The critical chain length required to maintain a stable nucleus in the bulk homopolymers was a constant value for each homologous series. It varied between 9 to 12 carbon atoms. When heats of fusion were determined in the presence of methanol, main‐chain restraints were freed, thus permitting more methylene groups to enter the crystal lattice. Hence, the heats of fusion, the crystallinity, and melting points increased above that of the bulk state. The magnitude of the contribution to the heats of fusion by each methylene group indicated that the hexagonal paraffin crystal modification prevailed in these homopolymers, in agreement with x‐ray data from the literature.

synopsisThe heats of fusion and the melting transitions of the crystallinity present in the side chains were determined for selected copolymers incorporating n-octadecyl acrylate or vinyl stearate. A major purpose of this investigation was to ascertain the effect of INTRODUCTIONMuch interest has centeredl8.2 on the crystallization phenomenon in copolymers in which one co-unit of the main chain is capable of crystallizing. The Flory theory of the equilibrium crystallization of polymers3 required that sequence length distribution, and not the chemical nature of the amorphous component, determbed the melting point depression. A very broad distribution of crystal sizes and lowered crystallinities were 3349 0

SummaryA laboratory survey of the properties of a series of ethenoxylated fatty acids and alcohols containing about 10, 15, 20, 30, and 40 ethenoxy groups per molecule has brought together information on solubility, cloud point, surface and interfacial tension, detergency, and wetting, foaming and emulsifying properties.Ethenoxylated alcohols were generally more soluble and had better wetting and foaming properties than the acids. Ethenoxylated acids had generally lower surface and interfacial tension values. Both types of nonionics appeared to be excellent emulsifying agents. Most of the ethenoxylated acids and alcohols were equally effective as built detergents. Built ethenoxylated oleic acid (n=10) and built hydroxy‐, dihydroxy‐, phenyl‐, and xylylstearic acids (n=20) were the best detergents.Nonionic surface‐active agents derivable from animal fats appeared to have an optimum range in the average number of ethenoxy groups per molecule, with respect to certain properties. The optimum was in the range of about 14 to 18 for wetting properties, the foaming properties of ethenoxylated alcohols, and the interfacial tension of ethenoxylated acids. This range is about equal to the value suggested for adequate solubility [3 less than the number of carbon atoms in the parent alcohol (3)] but somewhat higher than the general rule for maximum detergency [2/3 the number of carbon atoms in the parent acid or alcohol (1,5)].The rate of the reaction of octadecanol and stearic acid with ethylene oxide was compared. The alcohol reacted faster, in a non‐specific manner. The acidity of the carboxyl group of stearic acid promoted conversion to ethylene glycol monostearate before further ethenoxylation occurred. After disappearance of the carboxylic acid the rate of the reaction of the ethenoxylated acid approached that for octadecanol. A reaction mechanism consistent with these results is proposed.

synopsisMechanical and solution properties, melting transitions, torsional stiffness temperatures, Tf, and selected modulus-temperature curves are presented for copolymers of the N-n-alkylacrylamides with vinylidene chloride. Copolymers were prepared at 6OoC across the range of compositions, using &s comonomers N-n-butyl-, octyl-, dodecyl-and oleyl-acrylamide, which have amorphous side-chains, and N-n-octadecyl acrylamide and n-octadecyl acrylate whose side-chains are crystalline. The mechanical properties reflected the effect of the decline in backbone crystallinity and the simultaneous development of strong intermolecular interactions in the amorphous stage. Copolymers were stiff or showed brittle failure across the compositional range except when intermolecular forces were reduced (with n-octadecyl acrylate) and side-chain crystallization eliminated (with N-oleylacrylamide). These systems and the n-dodecylacrylamide copolymers had yield strengths less than brittle strengths and substantial elongations.Backbone crystallinity w&s eliminated a t about 15 mole % amide and side-chain crystallinity vanished at less than 10 mole yo of the amide in the N-n-octadecylacrylamide series. No depression in side-chain melting point occurred with dilution by segments of vinylidene chloride. Over-all decline in the flex-temperature was the normal monotonic function of composition except that values increased in magnitude at high vinylidene chloride contents, the effect presumably being caused by the presence of crystallinity.An empirical equation was developed which permitted the calculation of Tf for any N-n-alkylacrylamide composition with any number of carbon atoms in the side-chain, above 3.