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  • Chemistry  (8)
  • nonlinear optical polymers  (1)
  • 1995-1999  (8)
  • 1
    Electronic Resource
    Electronic Resource
    Polymers degradable under environmental conditions through end-modification of poly(α-methylstyrene) derivatives (1997)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 247 (1997), S. 163-178 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: To induce degradabilities in polymers in response to environmental conditions, the end-modification reactions of poly(α-methylstyrene) derivatives were carried out. When diphenylphosphine chloride was used as a modifier for the living end of para-substituted PMS, the coupling efficiency was ca. 50%. 2-Phenylallyl halide derivatives such as 2-phenylallyl bromide, 2-(4-tolyl)allyl bromide, and α-trifluoromethylstyrene were found to be suitable end-modification agents. For example, ω-2-phenylallyl PMS was prepared with almost quantitative functionality by the reaction of the living PMS with 2-phenylallyl bromide. In a similar way, ω-3,3-difluoro-2-phenylallyl and ω-2-(4-tolyl)allyl PMS derivatives were synthesized. Based on thermogravimetric analysis, onset of the degradation temperature of the end-modified PMS derivatives decreased in the following order: ω-hydrogen- 〉 ω-3,3-difluoro-2-phenylallyl- 〉 ω-2-phenylallyl- 〉 ω-2-(4-tolyl)allyl-PMS. Actually, the onset temperature of ω-2-(4-tolyl)allyl-PMS derivatives was 50°C lower than that of ω-H-PMS derivatives. These results indicate that the active species is produced effectively at the end unsaturated bond, which initiates the depolymerization of the polymer at rather low temperatures. Ionic degradation of these polymers was also investigated using butyllithium as an anionic initiator and methanesulfonic acid as a cationic initiator. Tendencies similar to the thermal degradation were observed. Therefore, it is concluded that a 2-phenylallyl substituent at the end of the PMS chain induces effective degradation through several mechanisms such as radical, anionic and cationic depolymerization reactions.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1997.052470111
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  • 2
    Electronic Resource
    Electronic Resource
    Water-soluble silicon containing polymer resist (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 2827-2833 
    Details
    ISSN: 0887-624X
    Keywords: poly(divinylsiloxyethylene glycol) ; PVSE ; polycondensation ; electron-beam resist ; lower critical solution temperature (LCST) ; hydrolytic stability ; oxygen reactive ion etching (O2 RIE) resistance ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(divinylsiloxyethylene glycol), which consists of alternating oligo(ethylene glycol)s (MW = 300) and divinylsiloxanes were prepared by a polycondensation reaction (Mn = 6500-9300, Mw/Mn = 2.01-2.27). The obtained polymer (PVSE300) showed a lower critical solution temperature (LCST) at 10.5°C, meaning that the polymer was soluble in water below the LCST. The glass transition temperature (Tg) and onset temperature of degradation (Td) of the PVSE300 were -72.5 and +317.5°C, respectively. The hydrolytic stability of the PVSE300 in aqueous media was also examined and it was found that PVSE300 was fairly stable in cold water. The lithographic characteristics of PVSE300 were examined against UV and electron-beam (EB) exposure and it was found that the PVSE300 film showed a negative character when developed by cold water. The photosensitivity parameter, Dg50, which denotes the dose at half remaining film thickness after development, against EB exposure was extremely high (1.0 μC/cm2) when a probe current and an accelerating voltage was 100 pA and 20 kV, respectively. A high durability for O2 reactive ion etching (O2 RIE) was also observed. The characteristics of PVSE300 against photoirradiation were also examined. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2827-2833, 1997
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Study of the thermal degradability of poly(α-methylstyrene) with modified end groups (1996)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 17 (1996), S. 123-129 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: To induce degradabilities in polymers in response to environmental conditions, endm odification reactions of poly(α-methylstyrene) (PMS) derivatives were carried out. 2-Phenylallyl halide derivatives such as 2-phenylallyl bromide, 2-(p-tolyl)allyl bromide, and α-trifluoromethylstyrene were found to be suitable end-modification agents. For example, the ω-2-phenylallyl-PMS derivative was prepared with almost quantitative functionality by the reaction of the living PMS derivative with 2-phenylallyl bromide. In a similar way, ω-3,3-difluoro-2-phenylallyl- and ω-2-(4-toly)allyl-PMS derivatives were synthesized. Based on thermogravimetric analysis, the onset of the degradation temperature of the endmodified PMS derivatives decreased in the following order: ω-hydrogen- 〉 ω-3,3-difluoro-2-phenylallyl- 〉 ω-2-phenylallyl- 〉 ω-2-(p-tolyl)allyl-PMS. Actually, the onset temperature of ω-2-(p-tolyl)allyl-PMS derivatives was 50°C lower than that of ω-H-PMS derivatives. These results indicate that the active species is produced effectively at the endunsaturated bond, which initiates depolymerization of the polymer at rather low temperatures. Therefore, it is concluded that a 2-phenylallyl substituent at the end of the PMS chain induces effective degradation through a radical mechanism.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1996.030170208
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  • 4
    Electronic Resource
    Electronic Resource
    A novel synthesis of semitelechelic functional poly(methacrylate)s through an alcoholate initiated polymerization. Synthesis of poly[2-(N,N-diethylaminoethyl) methacrylate] macromonomer (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 18 (1997), S. 827-835 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Potassium alcoholate was found to initiate the anionic polymerization of 2-(N,N-diethylaminoethyl) methacrylate (AMA) to form poly[2-(N,N-diethylaminoethyl) methacrylate] (PAMA). The molecular weight of the polymers was controlled by the monomer-initiator ratio with a narrow molecular weight distribution. Increased reactivity of the initiator by chelation of the monomer to the cation may be important for the polymerization. Using potassium (4-vinylbenzyl) alcoholate as an initiator, PAMA having a vinylbenzyl group was prepared which is a macromonomer having pH sensitive amino groups in each monomeric unit. By radical copolymerization with styrene, the PAMA macromonomer was incorporated as a graft chain.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1997.030180911
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  • 5
    Electronic Resource
    Electronic Resource
    Poly(silamine)s as new electron-beam resist materials (1996)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 17 (1996), S. 51-58 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Several types of poly(silamine)s were prepared and their structure-characteristics relationships were investigated. When a phenyl ring in the organosilyl unit and/or a cyclic structure in the amino unit was introduced, the glass transition temperatures were increased significantly in order to increase film formability. From the thermogravimetric analysis of the poly(silamine)s, it was found that the thermal decomposition of poly(silamine)s starts at ca. 380-400°C. On electron-beam irradiation of the poly(silamine) films, degradation of the polymer took place. On the basis of these results, poly(silamine)s can be one of the candidates for new positive-type polymeric resists.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1996.030170108
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  • 6
    Electronic Resource
    Electronic Resource
    Poly(divinylsiloxyethylene glycol)  -  synthesis and photoresist characteristics (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 18 (1997), S. 31-36 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly(siloxyethylene glycol) The term “poly(siloxyethylene glycol)” was used by us in our previous paper10 for the following polymer skeleton: with pendant vinyl groups (PVSE) was synthesized by polycondensation of oligo(ethylene glycol) (MW = 300) and diaminodivinylsilane. PVSE300 thus obtained is soluble in cold water. The PVSE300 coupled with a polythiol compound shows properties of a negative working photoresist. A negative tone image was obtained by development with water at 4°C. PVSE300 is a new type of Si-containing polymer resist which can be developed by water.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1997.030180105
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesis of organosilicon-containing macromonomers through an anionic polyaddition reaction (1995)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 196 (1995), S. 513-519 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Lithium diisopropylamide (LDA) induces metalation reaction of 4-(trimethylsilylmethyl)-styrene (SMS) to form lithiated SMS (SMSLi). SMSLi initiates the anionic polymerization of SMS to form oligomers with a polymerizable vinyl end-group. Mechanistic studies revealed that the propagation proceeds mainly by the addition reactions of SMSLi to the double bond of preformed oligomers in the early stage of the polymerization. In the later stage of the polymerization, propagations between preformed oligomers take place concurrently. The extent of polyaddition enchainments in the oligomers was found to increase when the reaction was carried out keeping the monomer concentration as low as possible. Reactivities of the organosilicon-containing macromonomers were also estimated by UV, MO calculations, and radical homopolymerization.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1995.021960207
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  • 8
    Electronic Resource
    Electronic Resource
    Photocrosslinkable second-order nonlinear optical polymers synthesized by cationic copolymerization (1995)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 6 (1995), S. 626-631 
    Details
    ISSN: 1042-7147
    Keywords: vinyl ethers ; nonlinear optical polymers ; poling ; photocrosslinking ; temporal stability ; 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
    Notes: Photocrosslinkable second-order nonlinear optical (NLO) polymers were synthesized from cationic copolymerization of a vinyl ether monomer bearing 4′-nitrobiphenyl-4-oxy group as the NLO chromophore with a vinyl ether monomer bearing cinnamoyl group as the photoreactive moiety. To obtain a suitable poling method involving photocrosslinking, which is capable of inducing a higher and more stable second-order nonlinear coefficient, d33, for NLO polymer films, some poling procedures were investigated. An optimized poling method was as follows. Ultraviolet (UV) irradiation is performed for 90 sec during poling at 50°C for 20 min, followed by poling at 150°C for 20 min. By using this poling method NLO polymer films exhibited a higher and considerably stable d33 value at room temperature, even though they had rather lower glass transition temperatures before photocrosslinking. Some photocrosslinking mechanism for NLO polymers investigated here were considered.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1995.220060906
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