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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.

Seed oils ofEuphorbia lagascae Spreng. andVernonia anthelmintica (L.) Willd. were prepared, refined and epoxidized; trivernolin was prepared fromV. anthelmintica and also epoxidized. These products were each comparatively evaluated as plasticizer‐stabilizers for polyvinyl chloride against commercial controls. EpoxidizedEuphorbia andVernonia oils and epoxidized trivernolin have potential value as primary plasticizers with the added advantage of increased heat and light stability; they could also be used in combination with other plasticizers utilizing the latter properties. Crude and refinedEuphorbia andVernonia oils are not considered suitable primary plasticizers because of poor compatibility and permanence; at low levels they probably could be used as stabilizers.

Random copolymers of N‐n‐butyl‐, N‐n‐octyl‐, or N‐n‐octadecylacrylamide with acrylonitrile were prepared in tert‐butanol at 60°C. to test the effect of amide homologs as internal plasticizers. At room temperature under high deformations all samples showed brittle failure; at 100°C. flexible and resilient copolymers were obtained. At low deformations, torsional stiffness values Tf followed the equations of Wood, Fox, and Dimarzio and Gibbs, the latter two modified by use of mole fraction instead of weight fraction. Mole fraction appeared to function better than weight fraction for these special cases where wi > 2mi and where modulus‐temperature curves were broad. Because literature values for the glass (or brittle) temperatures of homologs of poly‐n‐alkyl acrylates, methacrylates, n‐alkyl styrenes and alkenes, and estimated values for poly‐N‐n‐alkylacrylamides, plotted as a function of the logarithm of the number of single bonds in repeat units, extrapolate to an average value of −111°C. at a chain length of eighteen carbon atoms, and because side‐chain melting points of linear eighteen carbon side‐chain homologs appear to have a common value of 48–50°C. regardless of structure, it was concluded that similar glass and melting transitions are obtained when the side chain reaches eighteen carbon atoms in any series of homologs. Transitions for longer side‐chain lengths then approach the limit of a polyethylene graft, where Tg is −81°C. and Tm is 137°C.

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SynopsisMechanical properties were correlated with glass transition temperatures for a series of random copolymers of methyl methacrylate with comonomers selected from the higher n-alkyl acrylates and N-n-alkylacrylamides. The plasticizing comonomers were the n-butyl, Zethylhexyl, n-octadecyl, and oleyl acrylates, and the N-n-butyl-, N-noctyl-, N-n-octadecyl-, and N-oleylacrylamides. The complete range of compositions was investigated. However, the bulk of the data was obtained on compositions in the glassy region below the onset of the vitreous transition. In this region it was found that the decrease in tensile and flexural moduli and strengths with increase in internal plasticizer for all of the system was directly proportional to the decrease in T,,. It was concluded that the additive contribution to the free volume made by each side-chaii methylene group was alone responsible for the magnitude of the rate of change of properties. However, polar contributions of the amide group to stiffening the main chain exceeded those of the ester, so that the amides were less efficient plasticizers. An empirical equation was derived which described, with fair accuracy, the decrease in the mechanical parameters with composition for the amorphous copolymers. It was reasonably successful in predicting properties even into the composition range where the ambient testing temperature corresponded to or exceeded the transition temperature. In this transition region an accelerated decrease in the magnitude of the physical properties was observed. All samples exhibited brittle fracture except those tested in the transition region. Here the strain was largely irrecoverable flow. Side-chain crystallinity did not interfere significantly with the mechanical properties because moduli and strengths had already decayed to small values near the compositions where crystallinity commenced. Nonrandom copolymers of vinyl stearate and methyl methacrylate showed no internal plasticization, apparently because of macrophase aggregation.

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Methyl and butyl(acetoxyglycerol acetal) esters were prepared from 9(10)‐formyloctadecanoate or its dimethyl acetal. Mixtures of acetoxy mono‐ and diglycerol acetals, plus acetoxy mono‐, di‐, and triglycerol acetals, were prepared respectively from hydroformylated safflower and linseed methyl esters. The glycerol acetals were characterized with respect to physical, thermal, chromatographic, and spectroscopic properties. Acetoxy‐mixed glycerol acetals from safflower and linseed methyl esters were good primary plasticizers for poly(vinyl chloride) (PVC), whereas acetoxyglycerol acetals of hydroformylated methyl and butyl oleate were good secondary PVC plasticizers. As primary plasticizers, the poly(acetoxyglycerol acetal) esters showed less migration, better heat stability, and higher tensile strength than the generally used PVC plasticizer di(2‐ethylhexyl) phthalate.