A new technique is presented for making wool fabrics shrink resistant. Through interfacial polymerization polyamides, e.g., poly (hexamethylene sebacamide), are formed on the surface of the textile fibers. Fabric is padded consecutively through an aqueous solution of a diamine and a water-immiscible solution of a diacid chloride. Polymerization is extremely rapid and no heating or curing is required. Following the two-step padding, the fabric is simply washed and dried. Less than 5% resin on the fabric is required for dimensional stability in laundering. The wool fabrics treated are essentially unchanged in hand, flexural rigidity, break strength, percent elongation, and chemical resistance; they are improved in wrinkle recovery and smoothness after tumble drying.

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Copolymerizations of methacrylic anhydride and a variety of common types of vinyl monomers were conducted in bulk and in solution at 60–80° with benzoyl peroxide catalyst. The copolymers were characterized by conversion, solubility in hot dimethyl sulfoxide, elementary analysis, and infrared spectroscopy. A copolymer composition equation was derived for a special divinyl–vinyl system in which the divinyl monomer would cyclize extensively during polymerization and give rise to soluble, although perhaps branched, copolymers. The results showed that both soluble and insoluble copolymers were obtained, depending on the comonomer used and experimental conditions under which the copolymerization was carried out. In general, soluble copolymers were formed under the following conditions: (a) the less reactive the comonomer in free radical copolymerizations; (b) the greater the dilution; (c) the greater the difference in the moles of the two components in charge; and (d) the lower the conversion. According to reactivity ratio determinations and a comparison with published data, the anhydride ring radical behaved like a methyl methacrylate radical. The key step which led to gelation was believed to be “ring interruption” by the comonomer (CH2 = CHR): The question why methacrylic anhydride does not gel in homopolymerization, however, still remains unresolved.

The free‐radical polymerization of four acrylic anhydrides—methacrylic anhydride, acrylic anhydride, acrylic methacrylic anhydride, and acrylic propionic anhydride—under a variety of conditions has been studied. The polymers and their polyacid and polyester derivatives were characterized by solubility, infrared spectroscopy, and x‐ray diffraction. Methacrylic anhydride could be polymerized in bulk and in hydrocarbon solvents from −50°C. to 80°C. to give soluble, linear cyclopolymers in high conversions. In a polar solvent such as dimethyl sulfoxide, gelation would result at high monomer concentrations and at high conversions. Acrylic anhydride, however, appeared to become crosslinked more readily; soluble polymers could be obtained only by polymerization in nonpolar solvents. Most of the previous and somewhat conflicting results on the cyclopolymerization of these two monomers can now be reconciled by the present findings. The physical properties of cast poly(methacrylic anhydride) suggest that it has a stiff backbone with hindered functional groups and that the monomer itself was perhaps intramolecularly associated. Some improvements in the aqueous hydrolysis of poly(methacrylic anhydride) and in the esterification of the derived polyacid by diazomethane were described. By these refinements, poly(methyl methacrylate), derived from a −50°C. poly(methacrylic anhydride), had previously been shown to possess a novel, mixed syndiotactic and syndioduotactic (++−−++−−) configuration. Acrylic methacrylic anhydride could be cyclopolymerized very much like methacrylic anhydride. The polyacid and polyester derived from this unsymmetrical anhydride are expected to have unique structures; the acrylic or methacrylic units in the derivatives do not occur more than twice in succession. Acrylic propionic anhydride, when homopolymerized, readily changed to a soluble polymer and an unidentified, immiscible liquid. Its soluble copolymer with methyl methacrylate, however, could be crosslinked by heating. An intramolecular and intermolecular disproportionation reaction was postulated to explain these two interesting observations, respectively.

SynopsisBy means of interfacial polycondensation, ultrathin coatings of polynmides, polyurethanes, polyureas, polyesters, polyc:trbonates, and various copolymers can be formed on the surface of a substrate. If the substrate rontains reactive groups (such as --PU' H,, -OH, -NCO, -COCl, etc.), graft polymer is formed. The graft polymer is not) removed by extensive extraction with good solvents for the polymer. I n contrast, if wool is used as a substrate and is acetylated prior to the polymerization (to block the grafting sites), the thin coating of polymer is readily extracted. Digestion of the treated wool with enzymes that react with the wool, but not with the grafted coating, permits a characterization of the grafted polymer; amino acid analysis of the residue from the enzyme digestion provides evidence that the grafting sites on the wool are probably the free amino and hydroxyl groups located in the N-terminal amino acids or internal amino acids containing these groups in their side chain.