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2001 Volume 19 Issue 2
2001, 19(2): 123-127
Abstract:
A new process for lamination of polymer films by "bulk surface photografting" has been developed. The chemicalcomponent of the invention is that the curing of reactive solution between two substrates is initiated by the surface freeradicals produced by aromatic ketones and surface-hydrogen of substrates. Using the new approach, two or more polymerfilms are bonded together by a grafted polymer network which is grafted to adjacent substrate surfaces. The technique hasbeen applied to film substrates of different polymers such as polyolefins,polyesters,and polyamides which have abstractable hydrogens at the surface.The photolaminated film composites containing carrier films and an intermediate functional film of low permeability give strong laminates with high barrier properties,e.g.for oxygen and air.
A new process for lamination of polymer films by "bulk surface photografting" has been developed. The chemicalcomponent of the invention is that the curing of reactive solution between two substrates is initiated by the surface freeradicals produced by aromatic ketones and surface-hydrogen of substrates. Using the new approach, two or more polymerfilms are bonded together by a grafted polymer network which is grafted to adjacent substrate surfaces. The technique hasbeen applied to film substrates of different polymers such as polyolefins,polyesters,and polyamides which have abstractable hydrogens at the surface.The photolaminated film composites containing carrier films and an intermediate functional film of low permeability give strong laminates with high barrier properties,e.g.for oxygen and air.
PHOTOCHROMISM AND LUMINESCENCE OF DOPANT CHROMOPHORES THROUGH TWO-PHOTON IONIZATION IN POLYMER FILMS
2001, 19(2): 129-134
Abstract:
Two-photon ionization and recombination processes of an aromatic chromophore doped in polymer films werestudied and the features of these processes were discussed in relation to photofunctional polymers, An aromatic moleculehaving low ionization potential, e.g., N,N,N',N'-tetramethyl-p-phenylene diamine doped in poly(methyl methacrylate)(PMMA) film was easily photoionized by intense laser ligh excitation, giving a colored radical cation (photochromism) anda trapped electron in PMMA matrix. As a reversed process,the radical cation recombined with the trapped electron,showing discoloration and emitting luminescence,either isothermal luminescence(ITL),or thermoluminescence(TL).In this report,ITL and TL through the charge recombination process were studied and the luminescence was suggested as a mean of the read-out of photorecording.
Two-photon ionization and recombination processes of an aromatic chromophore doped in polymer films werestudied and the features of these processes were discussed in relation to photofunctional polymers, An aromatic moleculehaving low ionization potential, e.g., N,N,N',N'-tetramethyl-p-phenylene diamine doped in poly(methyl methacrylate)(PMMA) film was easily photoionized by intense laser ligh excitation, giving a colored radical cation (photochromism) anda trapped electron in PMMA matrix. As a reversed process,the radical cation recombined with the trapped electron,showing discoloration and emitting luminescence,either isothermal luminescence(ITL),or thermoluminescence(TL).In this report,ITL and TL through the charge recombination process were studied and the luminescence was suggested as a mean of the read-out of photorecording.
2001, 19(2): 135-145
Abstract:
Polymeric surfactants are amongst the most widespread of all polymers. In nature, proteins and polysaccharidescause self organization as a result of this surfactancy; in industry, polymeric surfactants play key roles in the food, explosivesand surface coatings sectors. The generation of useful nano- and micro-structures in films and emulsions as a result ofpolymer amphiphilicity and the application of mechanical stress is discussed. The use of X-ray and neutron small anglescattering and reflectivity to measure these structures and their dynamic properties will be described.New results on linear and dendritic polymer surfactants are presented.
Polymeric surfactants are amongst the most widespread of all polymers. In nature, proteins and polysaccharidescause self organization as a result of this surfactancy; in industry, polymeric surfactants play key roles in the food, explosivesand surface coatings sectors. The generation of useful nano- and micro-structures in films and emulsions as a result ofpolymer amphiphilicity and the application of mechanical stress is discussed. The use of X-ray and neutron small anglescattering and reflectivity to measure these structures and their dynamic properties will be described.New results on linear and dendritic polymer surfactants are presented.
2001, 19(2): 147-153
Abstract:
The fundamental optical storage mechanism of the laser light eddressable azobenzene moiety is briefly introduced.A modular and flexible synthesis design furnishes polyester matrices covalently integrating cyanoazobenzene in regularlyspaced side chains. Thin films of these materials are particularly well suited for holographic storape. Notable figures of meritsof liquid crystalline polyesters are response time to blue-green laser light of the order of nanoseconds, storage capacityexpressed as 5000 lines/mm, and high,permanent(almost nine years)diffraction efficiency of the order of 50% or greater,and erasability.The implications of the main chain nature for polyester morphology and for the permanency of the induced anisotropy are discussed.The design and methods of preparation of other significantly different polymer scaffolds supporting cyanoazobenzene are elaborated.Oligopeptides always result in amorphous materials,whereas copolymerthacrylates and dendritic or hyperbranched polyesters provide some materials that exhibit liquid crystallinity.However,none of these scaffolds affords materials that result in permanent anisotropy when exposed to interfering laser light.
The fundamental optical storage mechanism of the laser light eddressable azobenzene moiety is briefly introduced.A modular and flexible synthesis design furnishes polyester matrices covalently integrating cyanoazobenzene in regularlyspaced side chains. Thin films of these materials are particularly well suited for holographic storape. Notable figures of meritsof liquid crystalline polyesters are response time to blue-green laser light of the order of nanoseconds, storage capacityexpressed as 5000 lines/mm, and high,permanent(almost nine years)diffraction efficiency of the order of 50% or greater,and erasability.The implications of the main chain nature for polyester morphology and for the permanency of the induced anisotropy are discussed.The design and methods of preparation of other significantly different polymer scaffolds supporting cyanoazobenzene are elaborated.Oligopeptides always result in amorphous materials,whereas copolymerthacrylates and dendritic or hyperbranched polyesters provide some materials that exhibit liquid crystallinity.However,none of these scaffolds affords materials that result in permanent anisotropy when exposed to interfering laser light.
2001, 19(2): 155-160
Abstract:
By introducing semicrystalline moieties into hyperbranched molecular smictures three kinds of prepolymers of potential use as UV powder coatings were prepared and characterized.
By introducing semicrystalline moieties into hyperbranched molecular smictures three kinds of prepolymers of potential use as UV powder coatings were prepared and characterized.
2001, 19(2): 161-166
Abstract:
A series of dendrimer-encapsulated poly(phenyleneethynylene)s 4～6 were Synthesize d. The light-harvesting antenna functions of dendrimer frameworks together with the blue-light emitting activities of 4～6 were highlighted.
A series of dendrimer-encapsulated poly(phenyleneethynylene)s 4～6 were Synthesize d. The light-harvesting antenna functions of dendrimer frameworks together with the blue-light emitting activities of 4～6 were highlighted.
2001, 19(2): 167-173
Abstract:
The data referring to the mechanism and efficiency of electronically excited macroradical and radical anionreactions, the important role of photochemical chain reactions in polymers are presented, It was found that by varying photonenergy, temperature, photolysis time and competition between thermal and photochemical reactions, it is possible to change the functional composition and molecular weight distribution of polymers.
The data referring to the mechanism and efficiency of electronically excited macroradical and radical anionreactions, the important role of photochemical chain reactions in polymers are presented, It was found that by varying photonenergy, temperature, photolysis time and competition between thermal and photochemical reactions, it is possible to change the functional composition and molecular weight distribution of polymers.
2001, 19(2): 175-181
Abstract:
Three kinds of UV-curable self-emulsified polyurethane-acrylate (PUA) prepolymer, i.e., conventional, chainextended and grafted PUAs, were prepared. The relatively small particle size of the PUA dispersions indicates that the PUAprepolymers exhibit sufficient aqueous dispersibility. The PUA prepolymers can substantially lower the interfacial tension ofwater. Chain-extended PUA dispersions exhibit pseudoplastic behavior and thixotropy to a greater extent than do theirconventional counterpart. The chain-extended and grafted PUA photocure to higher conversion than do the conventional PU equivalent.The results of DSC measurement suggest that there exists phase mixing between the hard and the soft segment phases for the PUAs based on PEG 400 that is the comparatively short soft segment in the prepolymer.For the PUA prepolymers based on PEG having higher Mn values,chain-extending and grafting could impede the phase separation between the hard and the soft segment domains.The adhesion,impact strength and flexibility of the photocured films were tested.
Three kinds of UV-curable self-emulsified polyurethane-acrylate (PUA) prepolymer, i.e., conventional, chainextended and grafted PUAs, were prepared. The relatively small particle size of the PUA dispersions indicates that the PUAprepolymers exhibit sufficient aqueous dispersibility. The PUA prepolymers can substantially lower the interfacial tension ofwater. Chain-extended PUA dispersions exhibit pseudoplastic behavior and thixotropy to a greater extent than do theirconventional counterpart. The chain-extended and grafted PUA photocure to higher conversion than do the conventional PU equivalent.The results of DSC measurement suggest that there exists phase mixing between the hard and the soft segment phases for the PUAs based on PEG 400 that is the comparatively short soft segment in the prepolymer.For the PUA prepolymers based on PEG having higher Mn values,chain-extending and grafting could impede the phase separation between the hard and the soft segment domains.The adhesion,impact strength and flexibility of the photocured films were tested.
2001, 19(2): 183-187
Abstract:
The preparation technology of flame-retardant PC/ABS alloys was studied in this paper. Using a high-efficiencyflame retardant system and by means of multiple-ingredient compatibilizing, PC/ABS alloys with excellent impact strengthand flame retardant property were prepared. The experimental results showed that by using PS-g-MAH and SMA assynergistic compatibilizers, the notched Izod impact strength and flammability of PC/ABS alloy obtained in the present work can be up to 175 J/m and UL-94 V0, respectively.
The preparation technology of flame-retardant PC/ABS alloys was studied in this paper. Using a high-efficiencyflame retardant system and by means of multiple-ingredient compatibilizing, PC/ABS alloys with excellent impact strengthand flame retardant property were prepared. The experimental results showed that by using PS-g-MAH and SMA assynergistic compatibilizers, the notched Izod impact strength and flammability of PC/ABS alloy obtained in the present work can be up to 175 J/m and UL-94 V0, respectively.
2001, 19(2): 189-207
Abstract:
The recent developments in the photoinitiated cross-linking of polyethlene and the significant breakthrough of itsindustrial application are reviewed, The enhanced photo-initiation system, the dynamics of photoinitiated crosslinking, theoptimum conditions, the crystal morphological structures and related properties, and the photo- and thermo-oxidationstability of photocrosslinked polyethylene (XLPE) materials have been elucidated systematically. A new technique forproducing photocrosslinked XLPE-insulated wire and acble is described in detail.It can be expected that the future applications of photocrosslinking technique of polyolefins will be very promising.
The recent developments in the photoinitiated cross-linking of polyethlene and the significant breakthrough of itsindustrial application are reviewed, The enhanced photo-initiation system, the dynamics of photoinitiated crosslinking, theoptimum conditions, the crystal morphological structures and related properties, and the photo- and thermo-oxidationstability of photocrosslinked polyethylene (XLPE) materials have been elucidated systematically. A new technique forproducing photocrosslinked XLPE-insulated wire and acble is described in detail.It can be expected that the future applications of photocrosslinking technique of polyolefins will be very promising.
2001, 19(2): 209-216
Abstract:
A novel soluble ladderlike polysilsesquioxane containing reactive ester groups (Ester-T) was synthesized for thefirst time by stepwise coupling polymerization including preammonolysis, controlled hydrolysis and polycondensation. Themonomer, 3-trichlorosilylpropoxy 4-acetoxybenzoate (M), was synthesized by hydrosilylation of allyloxy 4-acetoxybenzoatewith trichlorosilane in the presence of dicyclopentadienylplatinum (II) chloride (Cp2PtCl2) catalyst. Combination of FTIR,1H-NMr,13C-NMR, 29Si-NMR, XRD,DSC,TGA and VPO methods was used to demonstrate that the polymer obtained has an ordered ladderlike structure.The synthesized Ester-T may have promising applications as a precursor of advanced functioanl polymers.
A novel soluble ladderlike polysilsesquioxane containing reactive ester groups (Ester-T) was synthesized for thefirst time by stepwise coupling polymerization including preammonolysis, controlled hydrolysis and polycondensation. Themonomer, 3-trichlorosilylpropoxy 4-acetoxybenzoate (M), was synthesized by hydrosilylation of allyloxy 4-acetoxybenzoatewith trichlorosilane in the presence of dicyclopentadienylplatinum (II) chloride (Cp2PtCl2) catalyst. Combination of FTIR,1H-NMr,13C-NMR, 29Si-NMR, XRD,DSC,TGA and VPO methods was used to demonstrate that the polymer obtained has an ordered ladderlike structure.The synthesized Ester-T may have promising applications as a precursor of advanced functioanl polymers.
2001, 19(2): 217-221
Abstract:
Functions of the polyamines in neutral rosin sizing were investigated using X-ray photoelectron spectroscopy(XPS) and laser diffraction particle analysis. The polyamine with a higher charge density and a smaller unite size could retainmore rosin and cover larger fiber surfaces. The XPS spectra demonstrated that polyallylamine.(PAAm) and polyvinylamine(PVAm) could react with a rosin size to form a -OC-N-CO- structure, but polydimethylamino ethyl methacrylate(PDMAEMA) could not. The formation of this structure may be a key step for effective sizing.
Functions of the polyamines in neutral rosin sizing were investigated using X-ray photoelectron spectroscopy(XPS) and laser diffraction particle analysis. The polyamine with a higher charge density and a smaller unite size could retainmore rosin and cover larger fiber surfaces. The XPS spectra demonstrated that polyallylamine.(PAAm) and polyvinylamine(PVAm) could react with a rosin size to form a -OC-N-CO- structure, but polydimethylamino ethyl methacrylate(PDMAEMA) could not. The formation of this structure may be a key step for effective sizing.
