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  • 1
    Electronic Resource
    Electronic Resource
    Studies on the radical chain copolymerization of methyl methacrylate and styrene at their azeotropic composition (1981)
    s.l. : American Chemical Society
    Macromolecules 14 (1981), S. 335-339 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma50003a021
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  • 2
    Electronic Resource
    Electronic Resource
    Studies on crystallization kinetics of nylon 6-polyoxypropylene-nylon 6 copolymers (1997)
    Springer
    Journal of polymer research 4 (1997), S. 81-89 
    Details
    ISSN: 1572-8935
    Keywords: Nylon 6-poly(oxypropylene)-nylon 6 triblock copolymers ; Composition ; Isothermal and nonisothermal crystalline kinetics mechanism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The crystllization kinetics of anionic-prepared nylon6-poly(oxypropylene) 1000-nylon 6 (NPN) block copolymers containing 1.20 to 8.76 wt% poly(oxypropylene)(POP) were studied. The thermograms of isothermal and nonisothermal differential scanning calorimetry of NPN block copolymers obtained were used for the study. The Avrami equation was used to analyze the isothermal crystallization of NPN nylon block copolymers. The Avrami exponent n obtained in the temperature range of 180 to 200 °C was 2.0 to 2.5. It was not similar to that for nylon 6 reported in literature. The activation energies of crystallization for the nylon block copolymers were smaller than that of nylon 6, and showed a minimum with POP content. The equilibrium melting point increased as the POP content decreased. For the nylon block copolymers with lower POP content, the slopes of Tc vs. Tm plots were higher than the values reported elsewhere. The Ozawa plot was used to analyze the data of nonisothermal crystallization. The obvious curvature in the plot indicated that the Ozawa model could not fit our system well, and there was an abrupt change of the slope in the Ozawa plot at a critical cooling rate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10965-006-0011-5
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  • 3
    Electronic Resource
    Electronic Resource
    A kinetic study on grafting of maleic anhydride onto a thermoplastic elastomer (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 3405-3415 
    Details
    ISSN: 0887-624X
    Keywords: maleated thermoplastic elastomer ; maleic anhydride ; graft ; kinetics ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Maleation of a thermoplastic elastomer, styrene-[ethylene-butylene]-styrene (SEBS) triblock copolymer, was carried out by a solution grafting reaction with maleic anhydride initiated by dicumyl peroxide. The reaction products from the graft reaction in xylene, commonly chosen as the solvent for maleation graft reactions, were identified using liquid chromatograph (LC), IR, and 13C-NMR. Side products from the graft reaction were identified by the LC analysis and, it was concluded that xylene affected the graft reaction through its active methyl groups. Reaction mechanisms were investigated by performing free radical kinetics analysis. The reaction orders and the apparent rate constant were estimated. It was concluded that a proper choice of the solvent might favor better graft efficiency. © 1993 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080311329
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  • 4
    Electronic Resource
    Electronic Resource
    Study on aqueous polymerizations of vinyl monomers initiated by metal oxidant-chelating agent redox initiators (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 3213-3222 
    Details
    ISSN: 0887-624X
    Keywords: redox initiators ; chelating type reductants ; metal oxidants ; mechanism ; characterization of kinetic parameters ; aqueous polymerizations of vinyl monomers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this study, a series of chelating type reductants containing redox pairs were tested as the initiator for aqueous polymerizations. The redox pairs consist of Ce(IV) or several first-row transition metals coupled with chelating agents of amino acids, dibasic acids, or diamine. The initial rates and limiting conversions of acrylamide polymerization initiated by those redox pairs were determined. The reductive reactivity of the chelating agents with Ce(IV) and the oxidative half-wave potential of Ce(III)-chelating agent/Ce(IV)-chelating agent were measured to evaluate the feasibility of these redox pairs as initiators. After the evaluation, the redox pairs other than Ce(IV)-amino acid type chelating agent were precluded to be promising initiators for aqueous polymerizations. Those Ce(IV)-amino acid type chelating agent redox pairs which could form at least two five- or six-membered rings were found to be potential initiators. The Ce(IV)-NTA pair was the most promising one. The mechanism of initiation of the redox pairs was proposed and further confirmed by the 13C- and 1H-NMR spectra of NTA-terminated polyacrylamide. The complex formation constants (K) and disproportionation constants (kd) of the Ce(IV)-amino acid type chelating agent redox initiators for acrylamide polymerization were evaluated. The factors governing the parameters of chelated complexes and the performance of polymerizations were discussed. These redox pairs were also used as the initiators for aqueous polymerizations of acrylic acid and acrylonitrile. © 1993 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080311307
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  • 5
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of segmented liquid crystal poly(azoxy polyester-co-polyoxypropylene) (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 165-173 
    Details
    ISSN: 0887-624X
    Keywords: segmented ; azoxy polyester ; polyoxypropylene 400 ; ratio of chain lengths ; thermotropic properties of mesophase ; flexible domain effects ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this study a series of a segmented copolyester, poly(4,4′-dioxy-2,2′-dimethyl-azoxybenzene dodecanedioyl) (PMABD)-co-polyoxypropylene 400 (POP), was prepared. The chain length of PMABD studied (n) was varied from 7.8-18.2, and that of POP was unchanged. The intrinsic viscosity of the segmented copolyesters was 1.04-1.30, and the number average molecular weight obtained was 2.53 × 104-3.49 × 104 g/mol. The mesophase texture and thermal properties of the segmented copolyesters were measured as functions of n. It was found that the insert of flexible POP between those liquid crystalline domains of PMABD did affect thermotropic properties of PMABD. As the n value was 9.0 and 7.8 (or 7.4 and 8.6% by weight POP) the texture appeared as cholesteric-like oily streaks. The effect could not be attained by simply copolymerizing a mesogenic moiety with a pair of spacers of different lengths. The fluidity and domain structure of the flexible dodecanedioyl-POP-dodcanedioyl segments are taken into account for the obtained results. © 1995 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080330119
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  • 6
    Electronic Resource
    Electronic Resource
    The effect of sodium methacrylate on the soapless emulsion copolymerization of methyl methacrylate and n-butyl acrylate (1991)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 29 (1991), S. 709-718 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The soapless emulsion polymerization of methyl methacrylate (MMA) and n-butyl acrylate (BA) containing various concentrations of sodium methacrylate (NaMA) or methacrylic acid (MMA) is studied. The hydrosoluble yields in final latexes are not larger than 1.3-5%, depending on the concentration of NaMA used. Below 25% conversion, the change of conversion with reaction time follows the square rule and the particle size is proportional to the 2/3 power of time. Above 25% conversion, serious gel effect occurs, and the conversion follows the seventh power on time and the growth of particle diameter obeys the 2.5 power on time. The multiple glass transition (Tg) occur below 20% conversion, where monomer droplets exist. NaMA added induces more Tgs. The effect of molecular weight of the copolymers obtained on Tg (even the molecular weight distributions were shown to be shouldertype bimodal) is estimated to be insignificant. Thus, the heterogeneity of copolymer compositions for multiple Tgs is ascribed to be caused from neither the molecular weight heterogeneity nor the shifts in compositions due to the difference of the monomer reactivity ratios. Referring to the results mentioned, we assume the sublayer surrounding the particle, rich with SO4- and COO- groups, and the concentration gradients of monomers in particles to illustrate particle morphology. In addition, the relatively hydrophilic sublayer is proposed to be closely relative with the occurrence of the composition heterogeneity in particles.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1991.080290513
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  • 7
    Electronic Resource
    Electronic Resource
    Aqueous polymerization of acrylamide initiated by cerium(IV)-amino acid chelating agent redox initiators (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 267-274 
    Details
    ISSN: 0887-624X
    Keywords: amino acid type chelating agents ; Ce(IV) redox initiators ; aqueous polymerization of acrylamide ; kinetics and parameters ; structure correlations ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Amino acid-type chelating agents such as nitrilotriacetic acid (NTA), nitrilotripropionic acid (NPA), iminodiacetic acid (IDA), and ethylenediamine tetraacetic acid (EDTA) were used in combination with cerium(IV) ammonium nitrate [Ce(IV)] as the redox initiators for the aqueous polymerizations of acrylamide (AM). The polymerization behaviors and polymer qualities were studied as functions of the concentrations of Ce(IV), chelating agent, AM, as well as temperature. The performances of the chelating agent redox systems varied with the natures of the chelating agents. The NTA-Ce(IV) initiator showed the most promising polymerization rate and conversion. The blank tests for the reactions of cerium and chelating agents were also conducted for finding mechanism of formation of free radicals and determining their complex formation constants (K) and disproportionation constants (kd). The mechanism for the polymerization was proposed and the kinetic parameters were evaluated. © 1993 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080310131
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  • 8
    Electronic Resource
    Electronic Resource
    Aqueous polymerization of acrylamide initiated by oxygenated cobalt(III) triethylenetetramine complex (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1115-1123 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polymerization of acrylamide was thermally initiated by the oxygenated cobalt(III) triethylenetetramine complex. Rate, conversion, and molecular weights obtained are favorable comparable to those initiated by K2S2O4 and K2S2O8 initiators. An induction period is about 3 mins. The value of Kdf at 60°C is 6.75 × 10-5 s-1, and the chain transfer to monomer constant is 1.2 × 10-5. The rate dependence obtained are a half order on the initiator concentration and a 1.38 order on the monomer concentration. The mole fraction of combination termination occurred in the overall termination reactions evaluated is 0.746.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1988.080260413
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  • 9
    Electronic Resource
    Electronic Resource
    Aqueous polymerization of acrylamide initiated by cerium (IV)-ethylenediamine tetraacetic acid redox system (1992)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 2459-2466 
    Details
    ISSN: 0887-624X
    Keywords: EDTA-Ce(IV) redox initiator ; aqueous polymerization ; acrylamide ; rate dependence ; mechanism ; kinetic parameters ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ethylenediamine tetraacetic acid (EDTA) terminated polyacrylamide was obtained by using the EDTA-cerium(IV) ammonium nitrate [Ce(IV)] redox initiator in the aqueous polymerization of acrylamide. The polymerization behaviors as a function of the concentration of Ce(IV), EDTA, and acrylamide as well as temperature were studied. The consumption rate of cerium(IV) depends a first-order reaction on the ceric ion concentration ([Ce(IV)]). The complex formation constant (K) and disproportionation constant (kd) of Ce(IV)-EDTA chelated complex are 1.67 × 104 and 3.77 × 10-3, respectively. The rate dependences of polymerization on monomer concentration and EDTA concentration both follow a second-order reaction in the run of initial monomer concentration ([M]i) equal to 0.2 mol dm-3. The number average molecular weight increases linearly with the ratio of [M]i/[Ce(IV)]i. The mechanism and kinetics for the polymerization was proposed. The kinetic parameters involved were determined. © 1992 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1992.080301120
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  • 10
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of terminally carboxyl ethylene glycol monomethyl ethers-substituted side-chain liquid-crystalline polysiloxanes (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 2423-2436 
    Details
    ISSN: 0887-624X
    Keywords: liquid-crystalline polymer ; side-chain ; mesophase ; smectic phase ; nematic phase ; crown-ether ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Alkene monomers containing phenyl or biphenyl carboxylate benzoate ester based on a mesogenic group of varied lengths of carboxyl oligo (ethanediol) monomethyl ethers as the terminal were synthesized. They were grafted onto poly(methyl-hydrosiloxane) by the platinum-catalyzed hydrosilylation process. The thermal transition temperatures and mesophase textures of monomers and of polymers were characterized by using differential scanning calorimetry (DSC), x-ray diffraction, and polarized optical microscopy with a hot stage. The factors governing mesophase textures and thermal transition temperatures are discussed. © 1993 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080311002
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