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  • Polymer and Materials Science  (14)
  • Poly(vinyl acetate) emulsion  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Experimental study and clinical use of poly(vinyl acetate) emulsion as liquid embolisation material (1994)
    Springer
    Neuroradiology 36 (1994), S. 634-641 
    Details
    ISSN: 1432-1920
    Keywords: Poly(vinyl acetate) emulsion ; Polymer microparticle ; Liquid emoblisation material ; Arteriovenous malformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A new material, an emulsion of poly(vinyl acetate) was experimentally developed and clinically used to overcome several disadvantages in currently used liquid embolisation materials. The emulsion microparticles, 0.3–0.7 μm in size, possessed cationic charge on the surface and hence aggregated immediately on contact with fluids containing anions. This inert polymer has the advantage that it does not induce a deleterious reaction in living tissue. Moreover, its medium is water and it is not adhesive, like the cyanoacrylates. Several concentrations of emulsion were injected into the renal arteries of dogs. For the investigation of tissue reactions and the possibility of recanalisation, the emulsion was injected into rats both subcutaneously and into the renal arteries. The renal artery injections in dogs showed adequate radiopacity and consistent complete occlusion. The lower the concentration of the emulsion, the smaller the arteries which could be occluded. Even at very low concentrations, however, venous occlusion did not occur. Histological study of the embolised rat kidney revealed no detectable damage in the vessel wall and no recanalisation for up to 6 months. The subcutaneously injected PVAc emulsion elicited mononuclear cell infiltration and gradual centripetal fibrosis, without any deleterious effect on the surrounding tissue. A cerebral arteriovenous malformation (AVM) was embolised using the material. Histology of the resected nidus showed findings similar to those in the animal experiments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00600429
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  • 2
    Electronic Resource
    Electronic Resource
    Graft polymerization of acrylamide onto UV-irradiated films (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 36 (1988), S. 1087-1096 
    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: Graft polymerization of acrylamide was attempted onto the surface of films preirradiated with UV radiation. The films employed are nylon 6, polypropylene, and ethylene-vinyl acetate copolymers. Following UV irradiation in air on films without photosensitizer, they were placed in monomer solution, degassed, and then heated to 50°C to effect the graft polymerization. After rigorous removal of homopolymers, polyacrylamide chains were found to be grafted in the surface region of the films to amounts up to several hundred micrograms per square centimeter of films. An ESCA study revealed the UV-irradiated but not yet grafted surfaces to be oxidized, and formation of peroxides was strongly suggested by the reaction of irradiated films with 1,1-diphenyl-2-picrylhydrazyl. It is likely that the initiator responsible for the graft polymerization is peroxides generated at and near the film surfaces upon UV irradiation. The grafted films became very slippery when contacted with water, in contrast with the films UV-irradiated but not yet grafted.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1988.070360509
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  • 3
    Electronic Resource
    Electronic Resource
    Photolysis of a fluorinated polymer film by vacuum ultraviolet radiation (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2215-2222 
    Details
    ISSN: 0887-624X
    Keywords: fluorinated polymer ; vacuum ultraviolet ; Xe lamp ; photolysis ; photo-oxidation ; surface modification ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We studied the photolysis of a fluoroethylene-fluoropropylene copolymer (FEP) film by vacuum ultraviolet (VUV) radiation from a resonance Xe lamp at a wavelength of 147 nm and air pressures of 0.05 and 2.5 Torr. The chemical changes in the FEP surface layer were investigated by Fourier-transform infrared spectroscopy with attenuated total reflection attachment and X-ray photoelectron spectroscopy. Double bonds were found to be the main product in the case of VUV treatment at 0.05 Torr, while photo-oxidation of FEP occurred predominantly by VUV treatment at 2.5 Torr under formation of the  - CF2C(O)F group. This oxygen-containing group was more effectively formed in the FEP surface layer by VUV photo-oxidation than by conventional surface oxidation techniques such as treatments by plasma and corona discharge and ozone. Storage of the VUV-treated polymers in air at 50% relative humidity resulted in hydrolysis of  - CF2C(O)F to the  - CF2COOH group. Substantial improvement of the film wettability was noticed after VUV photo-oxidation. These findings suggest that VUV irradiation provides a high potential for surface modification of fluorinated polymers which are known to be particularly resistant against functionalization by conventional surface modification techniques such as plasma treatment. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2215-2222, 1998
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Surface lubrication of polymer films by photoinduced graft polymerization (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 39 (1990), S. 489-498 
    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: Films of nylon 6, polypropylene, and ethylene-vinyl acetate copolymers were graft polymerized with acrylamide or dimethylacrylamide to render the hydrated surfaces slippery. Following UV irradiation in air, the films were placed in the aqueous monomer solution and then either heated to 50°C after degassing or UV-irradiated in the presence of a small amount of riboflavin without degassing to effect graft polymerization. The graft polymerization altered the films from the hydrophobic and nonlubricating to the hydrophilic and slippery surfaces. To evaluate the surface lubricity, the coefficient of friction (μ) against a glass plate in water was determined with the help of a tensile testing machine. The μ value for the films surface-grafted with acrylamide up to 30 μ g cm-2 was reduced to less than 0.05, regardless of the substrate polymers.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1990.070390301
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  • 5
    Electronic Resource
    Electronic Resource
    Graft polymerization of fluorinated monomer onto corona-treated PVA and cellulose films (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 48 (1993), S. 1825-1829 
    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: Surface graft polymerization of a hydrophobic monomer, 2,2,3,3,3-pentafluoropropyl methacrylate (5FMA), onto hydrophilic poly(vinyl alcohol) (PVA) and cellulose films was studied after corona discharge of the films. It was found that grafting strongly depended on the reaction medium; especially, addition of alcohol to the monomer greatly accelerated graft polymerization. For instance, when an ethanol/ water /5FMA mixture (65/25/10, by volume) was used as the polymerization medium. the PVA and cellulose films corona-discharged for a few minutes exhibited a high contact angle up to 100° after 30 min polymerization, the graft density being approximately 170 μg/cm2 for cellulose and 80 μg/cm2 for PVA. © 1993 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070481016
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  • 6
    Electronic Resource
    Electronic Resource
    In vitro hydroxyapatite deposition onto a film surface-grafted with organophosphate polymer (1994)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 28 (1994), S. 1365-1373 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: To produce a bone-bonding polymer surface that is capable of inducing deposition of a hydroxyapatite (HA) layer in the body fluid, an organophosphate polymer was covalently immobilized onto a high-density polyethylene film by surface graft polymerization of a phosphate-containing monomer. The grafted film was immersed in simulated physiologic solution (SPS). The chemical composition and structure of the formed apatite layer as well as its bonding strength to the polymer surface were investigated. To distinguish the effect of phosphate groups on the deposition of apatite layer from the simple calcium absorption by the anion, a comparative study was done using a polyethylene film with surface immobilized carboxylic groups. Calcium phosphate deposition was observed on all the materials investigated, but the kinetics, composition, deposit amount, and bonding strength of the new phase were found to be significantly different among the modified materials, depending on the density and chemical nature of the surface immobilized ionic groups. It was found that the polymeric materials modified by surface graft polymerization of a phosphate-containing monomer produce a carbonated HA layer firmly bonded with the material upon immersion in SPS. Carboxyl groups in the grafted layer was not enough to activate bonding with the HA layer. © 1994 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820281115
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  • 7
    Electronic Resource
    Electronic Resource
    Enhancement of bone formation by drawn poly(L-lactide) (1996)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 30 (1996), S. 553-558 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Poly(L-lactide) (PLLA) was molded into films and rods, and drawn in the longitudinal direction to endow them with piezoelectricity. The piezoelectric constants of PLLA films increased with the draw ratio and, after passing a maximum at a draw ratio around 5, decreased. PLLA samples with a draw ratio 5, underwent fibrilization. The PLLA rods were intramedullarily implanted in the cut tibiae of cats for internal fixation up to 8 weeks. Fracture healing was clearly promoted with increased callus formation as the draw ratio of the PLLA rod increased, whereas the undrawn PLLA as well as a polyethylene control rod had no effect on callus formation, or rather, retarded it. This finding strongly suggests that the promotion of fracture healing by fixation with drawn PLLA can be ascribed to the piezoelectric current generated by the strains accompanying leg movement. © 1996 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Grafting of proteins onto polymer surfaces with the use of oxidized starch (1979)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 13 (1979), S. 607-622 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A study has been carried out on the coupling of proteins onto crosslinked poly(vinylalcohol) hydrogel membranes and ethylene-vinyl alcohol copolymer(EVA) films pre-viously grafted with oxidized starches having many pendant aldehyde groups. The coupling reaction of proteins is based on the Schiff's base formation between the amino groups of proteins and the aldehyde groups of the oxidized starches which have been grafted onto the substrate membrane or film through acetalization of the aldehyde of starch with hydroxyl groups of the substrate polymers. The grafting of oxidized starches onto the EVA films seems to be restricted to the film surface, since no detectable change is observed in the weight and the attenuated total reflection infrared spectrum of the grafted films. The amount of grafted protein, determined by the ninhydrin method, reveals that, at least, plasma proteins such as serum albumin and fibrinogen are grafted to the film surface in a monomolecular layer without undergoing a marked denaturation. The α-amylase grafted onto the EVA film showed a distinct enzymatic activity in hydrolysis of amylose and starch, but the activity was very low compared with that of the ungrafted, soluble α-amylase.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820130407
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  • 9
    Electronic Resource
    Electronic Resource
    A new biological glue from gelatin and poly (L-glutamic acid) (1996)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 31 (1996), S. 157-166 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: This study describes the potentiality of hydrogels composed of gelatin and poly(L-glutamic acid) (PLGA) as a biological glue for soft tissues and compares its effectiveness with that of a conventional fibrin glue. Water-soluble carbodiimides (WSC) were used to crosslink the aqueous mixture of gelatin and PLGA. The mixed aqueous solution of gelatin and PLGA set to a hydrogel by use of WSC as rapidly as BOLHEAL® fibrin glue. An addition of PLGA to gelatin aqueous solution reduced not only its gelation time but also the WSC concentration necessary for hydrogel formation. The cured hydrogel exhibited firm adhesion to the mouse skin and other soft tissues with a higher bonding strength than BOLHEAL® fibrin glue. Cohesive failure in the hydrogel was observed when the gel-tissue bond was broken, in contrast to BOLHEAL® fibrin glue. The bonding strength of the gelatin-PLGA hydrogel became higher with the increasing PLGA concentration. The inflammatory reaction around the gelatin-PLGA hydrogel subcutaneously implanted in mice was mild, and the hydrogel was gradually absorbed with time in vivo. A toxicity test demonstrated that the concentration of WSC necessary as a biological glue was low enough not to induce its toxicity. © 1996 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Blood compatibility of hydrophilic polymers (1981)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 15 (1981), S. 697-718 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Blood compatibility has been studied for hydrophilic polymers such as poly(vinyl alcohol) (PVA), its derivative, and polyethylene grafted with water-soluble monomers. The surfaces in contact with electrolyte solutions have been characterized by measuring the zeta potentials. The study of plasma protein adsorption on these polymers has revealed that bovine serum albumin as well as bovine serum fibrinogen adsorbs to a lesser extent as the hydrophilicity of the polymers increases. Platelet deposition and fibrin formation, examined using platelet-rich plasma, have been found to take place less significantly on PVA as well as sodium acrylate- and acrylamide-grafted polyethylene than on nongrafted and acrylic acid-grafted polyethylene. Ex vivo experiments with canine whole blood have shown that formation of thrombus on PVA is less than on siliconized glass but increases upon heat treatment which reduces the hydrophilicity. When PVA tubes of about 1 mm diameter are anastomosed to the carotid artery of rat, the patency rate is found to depend strongly on the anastomotic technique. From the results on the zeta potential and the experiments in vitro and ex vivo it can be concluded that the material having a surface from which solvated, neutral chains are extended into the outer aqueous phase may exhibit excellent resistance to thrombus formation.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820150507
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