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  • 1
    Electronic Resource
    Electronic Resource
    Tacticity, molecular weight, and molecular-weight-distribution relationships in stereoregular polyacrylonitrile prepared by electron beam irradiation canal polymerization (2000)
    Springer
    Colloid & polymer science 278 (2000), S. 757-763 
    Details
    ISSN: 1435-1536
    Keywords: Key words Isotactic polyacrylonitrile ; Canal polymerization ; Electron beam irradiation ; Structure ; properties relationships
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The preparation and characterization of stereoregular isotactic polyacrylonitrile (PAN) by electron beam (EB) irradiation on a urea canal complex are described. The EB method has several advantages over the ordinary γ-ray irradiation method: a very short polymerization time is needed (within a few seconds) and EB irradiation is carried out intermittently, and so all the polymer properties can be studied as a function of the EB irradiation dose. The structure–properties relationships of PAN, such as intrinsic viscosity versus the number-average molecular weight and the viscosity versus the isotacticity range were clarified. Significant information for the optimization of the tacticity of PAN was extracted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003960000305
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  • 2
    Electronic Resource
    Electronic Resource
    Casting of organic glass by radiation-induced polymerization of glass-forming monomers at low temperatures. VI. Casting polymerization of methyl methacrylate prepolymer by irradiation (1978)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 22 (1978), S. 43-52 
    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: Casting of methyl methacrylate prepolymer by irradiation at relatively low temperatures was studied. It was difficult to completely glassify the methyl methacrylate monomer and prepolymer, and so the casting was carried out at temperatures above its melting point (-48°C). The optical strain formed in this stream remained of the stress type, and optical strain formation was reduced with increasing prepolymer concentration and decreasing temperature.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1978.070220104
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  • 3
    Electronic Resource
    Electronic Resource
    Durability of radiation-sterilized polymers, XI. The effect of irradiation on rubber gloves (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 40 (1990), S. 799-810 
    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: The effect of both gamma ray and electron beam irradiations on three rubber gloves are compared in relation to sterilization. Two of these gloves are sulfur vulcanized and the other is radiation vulcanized. It was found that the radiation-vulcanized rubber gloves could be used, even at 25 kGy, the sterilization dose used. For all three gloves, it was found that the tensile strength and elongation at break are not significantly affected after irradiation in either gamma rays or electron beam or during storage. The tear strengths, however, decrease with increasing dose and storage, and it was found that degradation was higher in gamma rays than electron beam. The chemiluminescence data show that the rate of degradation is the highest in latex film followed by radiation-vulcanized and sulfur-vulcanized gloves.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1990.070400516
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  • 4
    Electronic Resource
    Electronic Resource
    Casting of organic glass by radiation-induced polymerization of glass-forming monomers at low temperatures. IV. Casting and polymer properties of monomeric systems including polyfunctional monomers (1978)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 22 (1978), S. 13-26 
    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: The applicability to radiation-induced cast polymerization of polyfunctional monomers or systems including them was studied. Most of polyfunctional monomers could be glassified and were applicable to radiation casting. The effect of tetraethylene glycol diacrylate on inner-plasticized comonomer systems was studied in detail. It was found that the glass-forming property increased by the addition of tetraethylene glycol diacrylate and that heat durability improved satisfactorily. The formation of optical strain in casting was relatively easier in polyfunctional monomers including systems due to inner stress, although the merit of radiation casting was still obvious.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1978.070220102
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  • 5
    Electronic Resource
    Electronic Resource
    Radiation grafting of hydrophilic monomers onto poly(4-methylpentene-1), I. Grafting of acrylic acid (1987)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 149 (1987), S. 87-99 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die strahleninduzierte Pfropfung von Acrylsäure auf Poly(4-methylpenten-1) (TPX) mit unterschiedlicher Kristallinität ist bei verschiedenen Bedingungen untersucht worden. Freie Radikale, die durch Vorbestrahlung im Vakuum gebildet wurden, waren stabiler als die in Luft erzeugten Radikale und initiierten die Pfropfreaktion, sobald sie in Kontakt mit der Acrylsäure kamen. Die Pfropfgrade nahmen mit ansteigender Vorbestrahlungsdosis, Pfropftemperatur und Acrylsäurekonzentration zu. TPX geringer Kristallinität (24%) zeigte eine höhere Anfangspfropfgeschwindigkeit im Vergleich zu TPX höherer Kristallinität. Die Pfropfverteilung wurde mit einem Röngtenmikroanalysator beobachtet. Die Pfropfreaktion begann schrittweise von der Oberfläche des Films zum inneren Teil. In hochkristallinem TPX (34%) hängt die Pfropfverteilung im Endzustand von der Filmdicke ab, während sie in niedriger kristallinem TPX homogen und unabhängig von der Filmdicke war.
    Notes: Radiation grafting of acrylic acid (AAc) onto poly(4-methylpentene-1) (TPX) with different crystallinity has been investigated under various conditions. Free radicals formed by pre-irradiation of TPX in vacuum were more stable than those in the presence of air and might initiate the grafting reaction if come in contact with the AAc. Grafting yields increased with increasing preirradiation dose, grafting temperature, and concentration of AAc. Lower crystalline TPX (24%) showed a higher initial grafting rate compared with higher crystalline one. The distribution of grafting was observed by X-ray microanalyzer. The grafting reaction proceeded gradually with time from the surface of the film to the inner part. In high crystalline TPX (34%) the grafting distribution in the final stage depended on the film thickness, while in lower crystalline TPX it was homogeneous regardless the film thickness.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1987.051490106
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  • 6
    Electronic Resource
    Electronic Resource
    Durability of radiation sterilized polymers, XIVPart XIII cf.7.. The effect of nucleating agent on the melt behaviour of irradiated polypropylene (1990)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 182 (1990), S. 187-191 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Gamma-Bestrahlung von Polypropylen (PP) verringert dessen Molekulargewicht; die Abnahme ist in PP mit Keimbildner (NA) größer als in PP ohne NA. Bei DSC-Messungen liegt der Schmelzpunkt (Tm) von PP mit NA im ersten Durchlauf deshalb unter dem von PP ohne NA, wogegen es sich im zweiten Durchlauf genau umgekehrt verhält, da die in PP mit NA nach der Bestrahlung kürzeren Ketten nach dem ersten Durchlauf leichter kristallisieren können.
    Notes: By the addition of nucleating agent (NA), the molecular weight of gamma-irradiated polypropylene (PP) decreases more than that of PP without NA. In the first run of differential scanning calorimetric (DSC) measurement, the melting point (T m) of PP with NA was lower than the one without NA because of larger molecular scission which occurred during irradiation. On the contrary, in the second run, Tm of PP with NA, was found to be higher than that of PP without NA. Due to the presence of NA, the molecular chains become shorter during irradiation and therefore rearrangement of the chains is easier during crystallization after the first run, this contributes to an increase in Tm.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1990.051820113
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of styrene content and ZnO-stearic acid on the mechanical properties of radiation-vulcanized styrene-butadiene rubber (SBR) (1994)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 218 (1994), S. 11-21 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Der Einfluß des Styrolgehalts auf die Eigenschaften von elektronenstrahlvernetztem, rußgefülltem Styrol-Butadien-Kautschuk (SBR) war nur bei niedrigen Strahlungsdosen, d. h. geringen Vernetzungsgraden, ausgeprägt. Bei hohen Dosen wurde kein Effekt beobachtet, insbesondere für ZnO-enthaltenden SBR. Es wurde außerdem festgestellt, daß ZnO (3 phr) die Zugfestigkeit von SBR mit einem Styrolgehalt von 23,5 Gew.-% bei 20 kGy um 20% verbesserte, verglichen mit SBR mit 46 Gew.-% Styrol. Die Zunahme der Zugfestigkeit für gefüllten SBR (23,5%) betrug bei allen Strahlungsdosen nahezu 17%. Daneben waren Reißfestigkeit, Abrasionswiderstand und Bruchdehnung erheblich verbessert. Die hohe Effizienz von ZnO bei SBR (23,5%) könnte auf dessen höheren Butadiengehalt zurückzuführen sein. Das mechanische Verhalten von SBR (46%) bei 20 kGy war überraschend, da sowohl Zugfestigkeit als auch Bruchdehnung nahezu maximal waren.
    Notes: The effect of styrene content on the properties of electron irradiation-vulcanized SBR loaded with carbon black was pronounced only at low irradiation doses where the crosslinking densities were not so high. At high doses, no effect was observed especially for SBR containing ZnO. It was also observed that ZnO (3 phr) increased the tensile strength of SBR containing 23.5 wt.-% styrene by 20% at 20 kGy irradiation dose, compared to 5% at higher doses for SBR containing 46 wt.-% styrene. However, the increase in tensile strength by ZnO for loaded SBR (23.5%) was almost 17% at all irradiation doses. Besides, tear strength, abrasion resistance and elongation at break were remarkably improved. The high efficiency of ZnO toward SBR (23.5%) may be attributed to the higher butadiene content. The behavior of SBR (46%) at 20 kGy was surprising, since both tensile strength and elongation at break were almost maximum.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1994.052180102
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  • 8
    Electronic Resource
    Electronic Resource
    Radiation-induced graft polymerization of styrene onto poly(3-hydroxybutyrate) and its copolymer with 3-hydroxyvalerate (1997)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 250 (1997), S. 31-44 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Pfropfcopolymerisation von Styrol (St) auf Poly(3-hydroxybutyrat) (PHB) und auf dessen Copolymeres Poly(3-hydroxybutyrat-co-3-hydroxyvalerat) (P(HB-HV)) wurde unter gleichzeitiger Anwendung von Bestrahlungs- und Vorbestrahlungstechniken mit 60Co-γ-Strahlung durchgeführt. Der Pfropfungsgrad (Xg) von Styrol auf PHB erhöhte sich mit zunehmender Vorbestrahlungsdosis und Pfropfungstemperatur. Dagegen lag der Pfropfungsgrad des Copolymeren bei 50°C höher als bei 70°C. Verglichen mit der Pfropfung von Methylmethacrylat auf PHB und dessen Copolymeres wurden mit Styrol geringere Pfropfungsgrade erzielt. ESR-Untersu-chungen zeigten, daß die strahlungsinduzierten PHB-Radikale durch Addition von Styrol bei Raumtemperatur (25°C) zu Wachstumsradikalen für die Pfropfäste werden. Die Wachstumsradikale wurden ebenfalls bei 50°C und 70°C nachgewiesen, Pfropfreaktionen von Styrol auf PHB laufen bei diesen Temperaturen lebhaft ab. Die Abnahme der Radikalkonzentration im Verlauf der Reaktion stimmte mit dem Verbrauch an Radikalen in der Pfropfcopolymerisation überein. Das zahlenmittlere Molekulargewicht (Mn) der Pfropfcopolymeren war von den Pfropfbedingungen abhängig und verringerte sich mit zunehmender Reaktionstemperatur infolge vorzeitigen Radikalkettenabbruchs. Es zeigte sich, daß die Zunahme des Pfropfungsgrades bei einer Vorbestrahlungsdosis von mehr als 10 kGy für das Wachstum der Pfropfäste verantwortlich ist.
    Notes: Graft copolymerization of styrene (St) onto poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(HB-HV)) was carried out using simultaneous irradiation and pre-irradiation techniques with 60Co γ-rays. The degree of grafting (Xg) of styrene onto PHB increased with increasing pre-irradiation dose and grafting temperature while in the graft reaction of the copolymer, Xg was higher at 50°C than at 70°C. This Xg was lower than that in grafting methyl methacrylate (MMA) onto PHB and its copolymer. In the electron spin resonance (ESR) study, the PHB radical formed by irradiation was converted to a propagating radical by introducing St monomer at room temperature (25°C) for grafting. The propagating radical was observed even at 50°C and 70°C, grafting of St onto PHB occurs actively at such temperatures. The decay of the radical concentration during grafting well corresponded to radical consumption in graft polymerization. The molecular weight (M̄n) depended on the grafting conditions and the increase of the grafting temperature induced the formation of reduced M̄n because of early termination. It was confirmed that the increase of Xg in pre-irradiation of more than 10 kGy was due to the increment of the graft chain.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1997.052500103
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  • 9
    Electronic Resource
    Electronic Resource
    Effect of pre-irradiation on radiation stability of co-polypropylene (1995)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 227 (1995), S. 111-120 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Strahlungsbeständigkeit von vorbestrahltem Polypropylen mit 2,5 Gew.-% Ethylenanteil wurde mitr einem Copolymeren aus Polypropylen und einem nukleierenden Agens im Hinblick auf die Strahlungssterilisation von medizinischen Geräten verglichen. Die Transparenz des Propylen-Ethylen-Copolymeren wurde durch die Vorbehandlung verbessert. Im Vergleich mit der ebenfalls verbesserten Transparenz des Copolymeren aus Polypropylen und dem nukleierenden Agens wurde durch die Vorbestrahlung die Strahlungsbeständigkeit während der Bestrahlung und bei der Lagerung des bestrahlten Materials verbessert. Dies wird auf die geringere Kristallinität des vorbestrahlten Polypropylens aufgrund von bei der Bestrahlung gebildeten Verzweigungen zurückgeführt.
    Notes: The radiation stability of the pre-irradiated copolymer of polypropylene containing 2.5 wt.-% ethylene units is compared with a copolymer of polypropylene with a nucleating agent with regard to radiation sterilization of medical devices. It is found that transparency property of the propylene-ethylene copolymer is improved through pre-irradiation processes. This finding was compared with the co-polypropylene with nucleating agent which also gives a better transparency property. In comparison, it is found that pre-irradiated copolymer exhibits better radiation stability during irradiation and during storage after irradiation. The radiation stability of the pre-irradiated copolymer is due to its lower crystallinity caused by the formation of branches during the pre-irradiation process.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1995.052270111
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