Thermogravimetric analysis of vinylacetate‐vinylbutyrate copolymers

Meer, Robert van der; German, Anton L.

doi:10.1002/apmc.1976.050560103

Cited by 3 publications

(1 citation statement)

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“…It has a petaloid and a reduced stamen type of male sterility both of which have been collected from the wild (but from different populations) and male sterile morphology is cytoplasmically determined (Morelock, 1974). Other examples come from Knautia arvensis (Correns, 1906), A Ilium cepa (Jones and Einsweller, 1936;van der Meer, 1976) and from interspecies crosses in Nicotiana (Chaplin, 1964), Gossypium (Meyer and Meyer, 1961) and Brassica (Pearson, 1972). Variation in sex expression in Plantago lanceolata has been reported for more than a century by at least 17 different authors.…”

Section: Discussionmentioning

confidence: 99%

Gynodioecy in Plantago lanceolata L I. polymorphism for plasmon type

Damme

Delden

1982

Heredity

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SUMMARYStudies of the morphological polymorphism for the expression of male sterility in the gynodioecious species Plantago lanceolata revealed two separate series of stamen forms from sterile to fertile. The first type of complete male sterility (MSI) shows a disturbed development of the stamens, which are strongly reduced in size. The second type (MS2) has stamens which are petaloid. In the latter type the corolla and sometimes the pistil are also affected. Evidence is presented that these differences in expression of male sterility are cytoplasmically determined. The plasmon types are designated R and P respectively. In each plasmon type a series of intermediate sex forms occurs. Field counts showed that these intermediates are a non-negligible proportion of most populations. On the average MS1 reaches higher frequencies than MS2. Twenty two out of 27 populations appeared to be polymorphic for plasmon type. The remaining five populations are probably fixed for plasnion P and their distribution over the habitats studied suggests that the fitnesses of the different sex genotypes depend on environmental conditions.

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Section: Discussionmentioning

confidence: 99%

Gynodioecy in Plantago lanceolata L I. polymorphism for plasmon type

Damme

Delden

1982

Heredity

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Evaluation of monomer reactivity ratios of more complex copolymerization schemes, with application to the penultimate unit effect in methyl acrylate–butadiene copolymerization

Meer

Alberti

German

et al. 1979

J. Polym. Sci. Polym. Chem. Ed.

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A generally applicable computational procedure, which permits the accurate evaluation of the kinetic parameters of intricate and extended copolymerization schemes to be made, is described. This method is based on a numerical integration of the differential equation, and, according to the (improved) curve‐fitting I procedure, experimental errors in both measured variables are considered. Furthermore, a description is given of the F test, in which a statistical comparison between the resulting residual sums of squares of two different schemes offers a possibility of selecting the most probable kinetic scheme for a given copolymerization system. The capability and applicability of the methods developed is demonstrated for the free radical copolymerization kinetics of methyl acrylate (MA) (M1) and butadiene (BD) (M2) with toluene as solvent. Here, the simple copolymer equation is unsatisfactory because a significant penultimate unit effect in BD macroradical reactivity shows up: k222/k221 = 0.84, and k122/k121 = 0.53, and k11/k12 = 0.088. The microstructure of the copolymer samples, determined by infrared (IR) spectroscopy, shows a decreasing fraction of BD units in the vinyl configuration in favor of the fraction of BD units in the cis‐vinylene and trans‐vinylene configuration at increasing MA (m) content. Statistical considerations indicate a strongly diminished probability of finding BD (b) in the vinyl configuration in ∼mb∼ transitions. Steric hindrance or polar repulsion of the ester side group of the penultimate MA unit probably account for the increased preference for monomer addition to the C4 site over the C2 site of the BD macroradical.

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