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  • 1995-1999  (3)
  • 1990-1994  (3)
  • Polymer and Materials Science  (6)
  • 1
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of graft copolymers of methacrylonitrile/methacrylate mixtures onto amylomaize by the ceric ion method (1992)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 1541-1548 
    Details
    ISSN: 0887-624X
    Keywords: grafting ; starch ; methacrylonitrile/methacrylate mixtures ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Graft polymerizations of mixtures of methacrylonitrile with n-alkyl methacrylales onto amylomaize were carried out. The graft copolymers were characterized by both IR and 13C-NMR spectroscopies. The influence of the monomer feed on the grafting parameters has been studied. The variation of these parameters with the mole fraction of methacrylate in the feed for the first three systems studied, MAN/MMA, MAN/EMA and MAN/BMA, was similar: thus, percent grafting (%G, percent weight of grafted polymer with respect to grafted amylomaize), percent grafted amylomaize (%GA, percent weight of grafted amylomaize with respect to initial amylomaize), percent grafting conversion (%Cg, percent weight of grafted polymer with respect to initial monomer), and percent total conversion (%Ct, percent weight of total acrylic polymer with respect to initial monomer) were increased, but percent grafting efficiency (%GE, percent weight of graft copolymer with respect to total polymer) decreased. The system MAN/HMA presented values of grafting parameters lower than those of the previous systems. The optimum values were obtained at 0.6 HMA mole fraction in the monomer feed. When the number of carbon atoms of the n-alkyl group rises from 1 to 4, the increase of the n-alkyl group length gives rise to increases of the %G %Cg and %Ct values and decreases of the %GE and %GA values. For the largest methacrylate, the grafting reaction appears to be controlled by the lesser accessibility of the monomer to the active sites of the carbohydrate. © 1992 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1992.080300805
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Graft copolymerization of different mixtures of acrylic monomers on amylopectin. Swelling behavior (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 54 (1994), S. 577-584 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Hydroxylic and nonhydroxylic acrylates - methyl acrylate (MA), ethyl acrylate (EA), butylacrylate (BA), hydroxypropyl methacrylate (HPMA), ethylenglycol dimethacrylate (EGDMA), and mixtures of HPMA-MA, HPMA-EA, HPMA-BA in a 50/50 feed composition - were grafted onto amylopectin with different amounts of crosslinking agent, EGDMA. Percent of total conversion, percent crude grafting, and influence of pH in water content were studied. In this sense it was only at pH 10 when a real variation in the water content could be seen. It was also proved that the highest values were obtained when one of the comonomers was EGDMA with a 34 mol% of the initial feed composition. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1994.070540508
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis of graft copolymers of acrylic monomers onto amylose. II. Study of the ceric ion behavior (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 45 (1992), S. 981-986 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A study of the ceric ion consumption during graft polymerization of methyl acrylate (MA), ethyl acrylate (EA), ethyl methacrylate (EMA), and butyl methacrylate (BMA) with amylose was carried out. Grafted acrylic polymers were isolated by the acid hydrolysis method. Weight-average and number-average molecular weights were determined by gel permeation chromatography (GPC). The number of grafted chains (mmol) ranged from 8.70 × 10-3 to 12.35 × 10-3 for acrylates and from 3.20 × 10-3 to 6.80 × 10-3 for methacrylates. These results were related to others obtained from the ceric ion consumption studies.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070450605
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of crosslinking agents on acrylic bone cements based on poly(methylmethacrylate) (1997)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 37 (1997), S. 465-473 
    Details
    ISSN: 0021-9304
    Keywords: bone cement ; crosslinking agents ; PMMA ; mechanical properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Three different crosslinking agents were added to the monomer content of the bone cement formulation based on poly(methylmethacrylate), PMMA, in various concentrations, and their effects on the curing parameters and mechanical properties were determined. The different crosslinking agents were dimethacrylates containing a range of chain lengths and degrees of flexibility. For the parent formulation of the bone cement, PMMA powder was used, and the properties and kinetics of curing were compared for the same system with and without crosslinking agents. It was found that at low concentrations of crosslinking agents, the mechanical properties were superior but steadily decreased with increasing concentrations. Poly(ethyleneglycoldimethacrylate), EGDMA(400), even when used at very low concentrations, produced a steady improvement in the mechanical properties and could be used in cement formulations with a view to reducing creep and improving mechanical properties. © 1997 John Wiley & Sons, Inc. J Biomed Mater Res, 37, 465-473, 1997.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 5
    Electronic Resource
    Electronic Resource
    Application of long chain amine activator in conventional acrylic bone cement (1998)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 43 (1998), S. 131-139 
    Details
    ISSN: 0021-9304
    Keywords: self-curing acrylic resins ; acrylic bone cements ; tertiary amine ; poly(methyl methacrylate) ; lauroic acid derivative ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A long chain acid derivative bearing an aromatic tertiary amine group, 4-N,N-dimethylaminobenzyl laurate (DML), which acts as an activator for the curing of acrylic cements at low temperature, has been synthesized and characterized to reduce the biological adverse effects usually associated with the classical activator N,N-dimethyl-4-toluidine (DMT). The effectiveness of the activator was tested on commercial formulations (e.g., Palacos R®) and on experimental bone cements based on poly(methyl methacrylate) by using different benzoyl peroxide/amine molar ratios. The exotherms of polymerization were followed at three different temperatures: 25, 30, and 37°C. The DML activator was found to be more sensitive to temperature than the corresponding DMT. DML provided exotherms of polymerization with decreasing peak temperatures and increasing setting times without impairing the mechanical properties. Residual monomer content was analyzed in a range of activator concentrations by keeping the benzoyl peroxide concentration constant. In all cases the residual monomer content was lower than 5%, indicating its good efficiency in the benzoyl peroxide initiated polymerization. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 43: 131-139, 1998
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 6
    Electronic Resource
    Electronic Resource
    Application of tertiary amines with reduced toxicity to the curing process of acrylic bone cements (1997)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 34 (1997), S. 129-136 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: 4-Dimethylaminobenzyl alcohol (DMOH) and 4-dimethyl-aminobenzyl methacrylate (DMMO) were used as the activators in the benzoyl peroxide initiated redox polymerization for the preparation of acrylic bone cement based on poly(methylmethacrylate) beads of different particle size. The residual monomer content of the cured cements was about 2 wt %, independent of the redox system used in the polymerization, indicating that the activating effect of the tertiary aromatic amines DMOH or DMMO was sufficient to reach a polymerization conversion similar to that obtained with the benzoyl peroxide (BPO) N,N-dimethyl-4-toluidine (DMT) system. The BPO/DMOH and BPO/DMMO redox systems provided exotherms of decreasing peak temperature and increasing setting time, and the cured materials presented higher average molecular weight and similar glass transition temperatures in comparison with those obtained when DMT was used as the activator. In addition, these activators are three times less toxic than the classical DMT. © 1997 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
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