Study of photopolymer. XVII. Synthesis of novel photosensitive polymers with pendant photosensitive group and photosensitizer groups

Novel photosensitive polymers with pendant photosensitive group, such as cinnamic ester, and photosensitizer groups, such as N-carbamoyl-p-nitroaniline and N-carbamoly-4-nitro-1-naphthylamine, were synthesized from radical copolymerizations of (2-cinnamoyloxy)ethylmethacrylate with photosensitizer monomers, such as p-nitrophenylmethacrylamide and 4-nitro-1-na-phthylmethacrylamide, by using asobisisobutyronitrile (AIBN) in benzene and from the copolymerizations of (2-hydroxy)ethylmethacrylate or (2-hydroxy)ethylacrylate with photosensitizer monomers by using AIBN in DMF. This procedure was followed by condensation reactions of the copolymers with cinnamoyl chloride with pyridine as HCL acceptor in the same reaction flask. The photoreactivities of the polymers obtained were influenced by the concentration of photosensitive group and photosensitizer groups and their ratio in the polymer matrix. In addition, the photosensitivity of cinnamic ester groups attached to a soft polymer segment was higher than that of cinnamic ester group attached to a hard polymer segment when these polymers had the same pendant N-carbamoyl-p-nitroaniline group as photosensitizer. Furthermore, the spacer length between the polymer chain and photosensitizer group was important for increasing the photoreactivity of the photosensitive group in the polymers with pendant cinnamic ester and N-carbamoyl-p-nitroaniline groups.     

Syntheses of functional condensation polymer. I. Polyesters having pendant functional groups such as hydroxyl,formyl, aldoxime,aminomethyl and hydroxymethyl

Unsaturated polyesters having pendant functional groups such as hydroxyl, formyl, aldoxime, aminomethyl and hydroxymethyl, have been prepared and characterized, and some of their properties were investigated. Reaction conditions for the epoxidation of unsaturated polyesters and hydrolysis of the epoxy groups in the polyesters were established to control the amount of pendant diol groups. It was possible to incorporate up to 90 mole-% of formyl side groups into the unsaturated polyester by the hydroformylation with the rhodium catalyst. In addition, the formyl side groups of the modified polyester were converted into hydroxymethyl or aldoxime groups and were then converted to amino groups. The melting points of the modified polyesters decreased with increasing the pendant group content of the polyesters, as expected. Aliphatic polyesters having pendant hydroxyl or amino groups had a high affinity for moisture, which might be ascribed to the participation of the hydrophilic pendant groups in the modified polyesters.     

Preparation of a polypentenamer having pendant ionic groups and its hydrogenated derivatives

Polypentenamers having pendant carboxylate groups including esters, acids, and salts and their hydrogenated derivatives have been prepared and characterized, and some of their properties investigated. Reaction conditions were established to control the amount of pendant thioglycolate groups incorporated into the polypentenamer by the free-radical addition reactions of thioglycolic acid derivatives and subsequently to completely hydrogenate the polymers so formed, which contained thioglycolate contents ranging from less than 1 mole-% to about 16 mole-%, without backbone degradation and crosslinking reactions. The glass transition temperatures and the melting points of these polymers were observed to depend upon the pendant group content, as expected, but there appears to be little difference within these properties between polymers in which the pendant groups were in the salt form as compared to those of the corresponding carboxylic acid form. The thermal stabilities of the polymers having the pendant groups were somewhat lower than those of the parent polymers, apparently because of side reactions involving the thioglycolate groups. The calcium salt derivative showed a particularly low thermal stability compared to that of polymers with monovalent salts.     

Novel polymeric structures via the chlorination of cis-1,4-polybutadiene in the presence of aryl nucleophiles

The addition chlorination of cis-1,4-polybutadiene in the presence of a variety of aryl nucleophiles resulted in the formation of head-to-head poly(vinyl chloride) with pendant aromatic functional groups. Chlorination in methylene chloride solution with benzoic acid gave chlorinated polymers with pendant benzoate esters. Chlorination in the presence of phenol and benzhydrol provided polymers with pendent phenyl and diphenyl methyl ethers, respectively. Acetophenone participated during chlorination to affored polymer with pendant α-chloroether groups, while benzonitrile gave a polymer with pendant imidoyl chlorides. The extent of participation of these nucleophiles was estimated from elemental analysis and NMR spectral data, and the effect of aryl substitution on density, glass transition temperature, and linear coefficient of thermal expansion was determined. © 1993 John Wiley & Sons, Inc.     

Shape memory biomaterials prepared from polyurethane/ureas containing sulfated glucose

Covalently crosslinked polyurethane/urea polymers were synthesized using diamine monomers modified with pendant glucose groups and 2,4‐toluene diisocyanate, poly(ethylene glycol) (PEG), and 1,1,1‐tris(hydroxymethyl)ethane (triol) comonomers. The polymers showed shape memory behavior with a switching temperature dependent on the glass transition temperature. The glass transition temperature is tuned by varying the mole ratio between the glucose‐diamine and PEG used in the polymerization. Increasing PEG content resulted in decreasing glass transition temperature, and a glass transition temperature of 39 °C, close to physiological temperatures, was obtained. The fixed shape showed gradual shape recovery behavior, but a fixity of 70% was achieved when the material was stored at 25 °C. The polymer recovered to the permanent shape when heated to 50 °C. Finally, the surface of a film of the polymer can be sulfated to achieve increased blood‐compatibility without sacrificing the shape memory properties. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2252–2257     

Preparation and properties of new photosensitive polyimides from bis(4-aminophenyl)tetramethyldisilane and various aromatic tetracarboxylic dianhydrides

New photosensitive polymides containing photosensitive disilane unit were synthesised from 1,2-bis(4-aminophenyl)tetramethyldisilane and various aromatic tetracarboxylic dianhydrides by the usual two-step procedure that includes ring-opening polyaddition to yield the precursor polyamic acids, followed by cyclodehydration giving the respective polyimides. The polymaic acids had inherent viscosities between 0.63 and 0.85 dL/g depending on the tetracarboxylic dianhydride used. Excepting the polyimide obtained from pyromellitic dianhydride, all other polyimides were soluble in N-methyl-2-pyrrolidone, m-cresol, and pyridine. While the polyimide containing diphenyl sulfone unit was amorphous, the other polyimides were semi-crystalline polymers based on their x-ray diffractograms. The polyimides had glass transition temperatures between 235 and 304°C. They were thermally stable up to 380°C in both air and nitrogen atmospheres. All the polyamic acids showed a drastic decrease in the inherent viscosity upon UV light irradiation, implying the inherent photosensitivity of the polymers containing the disilane moiety.     

Novel surface fixation technology of hydrogel based on photochemical method: Heparin-immobilized hydrogelated surface

This article reports a novel photoinduced surface process technology enabling simultaneous hydrogel formation and its surface fixation on polymeric substrates. The process consists of layering two different types of photoreactive coatings on a polymeric surface, an azidophenyl-bearing polymer as an adhesive layer and cinnamoylated copolymer as a hydrogel layer, and subsequent UV irradiation. The photoreactive adhesive polymer coated on a substrate is poly(m-azidostyrene), in which photoreaction of phenyl azido groups is responsible for the chemical bonding between the substrate and hydrogel. N,N-dimethylacrylamide copolymer containing cinnamate moieties in their side chains, which undergo photocrosslinking via intermolecular dimerization, was applied as an overcoat on the adhesive layer. UV irradiation resulted in the formation of hydrogel chemically bonded onto the substrate. This was confirmed by ESCA measurements. A heparin-immobilized hydrogelated surface with controlled release characteristics was demonstrated. © 1993 John Wiley & Sons, Inc.     

Preparation and characteristics of photocross-linkable poly(vinyl alcohol)

The reaction of poly(vinyl alcohol) with styrylpyridinium and quinolinium salts which contain formyl group produced water-soluble photosensitive polymers. The sensitivity was high, although the content of the styryl groups was extraordinarily low. Spectroscopical studies revealed that the high sensitivity is due to the aggregation of photofunctional group in the polymer matrix which leads to cyclodimerization on exposure to ultraviolet (UV) light.     

Synthesis of new thermosetting poly(2,6‐dimethyl‐1,4‐phenylene oxide)s containing epoxide pendant groups

A new class of thermosetting poly(2,6‐dimethyl‐1,4‐phenylene oxide)s containing pendant epoxide groups were synthesized and characterized. These new epoxy polymers were prepared through the bromination of poly(2,6‐dimethyl‐1,4‐phenylene oxide) in halogenated aromatic hydrocarbons followed by a Wittig reaction to yield vinyl‐substituted polymer derivatives. The treatment of the vinyl‐substituted polymers with m‐chloroperbenzoic acid led to the formation of epoxidized poly(2,6‐dimethyl‐1,4‐phenylene oxide) with variable pendant ratios, and the structures and properties were studied with nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and gel permeation chromatography. The ratios of pendant functional groups were tailored for the polymer properties, and the results showed that the glass‐transition temperatures increased as the benzylic protons were replaced by bromo‐, vinyl‐, or epoxide‐functional groups, whereas the thermal stability decreased in comparison with the original polymer. Within a molar fraction of 20–50%, the degree of functionalization had little effect on the glass‐transition temperature; however, it correlated inversely with the thermal stability of each functionalized polymer. The thermal curing behavior of the epoxide‐functionalized polymer was enhanced by the increment of the pendant functionality, which resulted in a significant increase in the glass‐transition temperature as well as the thermal stability after the curing reaction. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5875–5886, 2006     

Synthesis,Characterization and Photocrosslinking Properties of Poly(1‐(4‐Methacrylamidophenyl)‐1‐(4‐nitrophenyl)prop‐1‐en‐3‐one)

The phenylmethacrylamide monomer, 1‐(4‐methacrylamidophenyl)‐1‐(4‐nitrophenyl)prop‐1‐en‐3‐one (MPNP) containing a photosensitive group was synthesized by reacting 4‐nitrocinnamoylaniline with methacryloyl chloride in the presence of triethylamine at 0–5°C. The functional monomer, MPNP was polymerized in ethyl methyl ketone (EMK) under nitrogen atmosphere at 70°C using benzoyl peroxide (BPO) as the initiator. The synthesized polymer was characterized by UV, IR, ¹H‐NMR and ¹³C‐NMR spectroscopy. The molecular weight data of the polymer as obtained from gel permeation chromatography suggests a higher tendency for chain termination by radical recombination than disproportionation. The thermal studies of the polymer were obtained from thermogravimetric analysis. The glass transition temperature of the polymer was determined by differential scanning calorimetry. The solubility of the polymer was tested in various organic solvents at room temperature. The photosensitivity of the polymer was investigated in various solvents in the presence and absence of triplet photosensitizers. The effect of the different solvents nature and concentration on the rate of photocrosslinking of the polymer were also examined for using the polymer as negative photoresist materials.     

Azobenzene‐containing LC polymethacrylates highly photosensitive in broad spectral range

Two photosensitive chiral liquid crystalline azobenzene‐containing polymethacrylates having different length of flexible spacer connecting chromophores with backbone were synthesized and their phase behavior and photo‐optical properties were studied. Both polymers consist of lateral methyl substituents in ortho‐position of azobenzene chromophores providing high photosensitivity even in red spectral region as well as high thermal stability of photoinduced Z‐form of azobenzene chromophores. It is shown, that smectic phase (SmA*) formation in films of polymer with longer spacer predetermines its quite unusual spectral response to UV and subsequent visible light actions. The SmA* phase promotes spontaneous homeotropic alignment of azobenzene chromophores in polymer films. UV‐irradiation induces not only E‐Z isomerization but also results in disruption of homeotropic alignment, whereas subsequent visible light action enables to obtain films with the low degree of chromophores orientation. The photo‐orientation phenomena under the action of polarized light of different wavelength on polymer films were studied. The possibility of using red polarized light of moderate intensity for optical photorecording on polymer films is demonstrated. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2962–2970     

Graft polymerization of methyl methacrylate initiated by pendant azo groups introduced onto γ-poly(glutamic acid)

The grafting of poly(methyl methacrylate) (PMMA) onto biosynthesized γ-poly(glutamic acid) (γ-PGA) initiated by pendant azo groups introduced onto γ-PGA was performed. The introduction of pendant azo groups onto γ-PGA was achieved by the reaction of carboxyl groups of γ-PGA with azo initiators having hydroxyl or amino groups, such as 2,2-azobis[2-(hydroxymethyl)propionitrile] (AHP), 2,2′-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] (AMHP), and 2,2′-azobis[2-(2-imidazolin-2-yl)propane] (AIP), using N,N′-dicyclohexylcarbodiimide. The amount of pendant AHP groups introduced onto γ-PGA was estimated to be 0.15 mmol/g. Untreated γ-PGA failed to initiate the polymerization of MMA. On the contrary, the polymerization of MMA was found to be initiated in the presence of γ-PGA having azo groups: the polymerization rate was proportional to the square root of the concentration of γ-PGA having pendant azo groups. During the polymerization PMMA was grafted onto γ-PGA; the percentage of grafting of PMMA onto γ-PGA obtained from the graft polymerization initiated by pendant AHP, AMHP, and AIP groups was evaluated to be 65.0, 53.1, and 29.0%, respectively. Differential scanning calorimetric analysis shows that the endotherm transition point of γ-PGA at 220°C disappears by the grafting of PMMA onto the polymer. © 1993 John Wiley & Sons, Inc.     

Synthesis of silsesquioxanes having photochromic diarylethene pendant groups

Silsesquioxanes having 1-(2-methylbenzo[b]thien-3-yl)-2-[5-(4-butylphenyl)-2,4-dimethylthien-3-yl]perfluorocyclopentenes as the pendant groups were synthesized. Photochemical conversion from the open-ring to the closed-ring form of diarylethenes chemically bonded to polymers was by 15–25% lower than the conversion of the chromophores dispersed in the same matrix. No appreciable difference in the photoconversion of the fixed chromophores was observed below and above the glass transition temperature (T_g) of the polymer films.     

Synthesis and characterization of novel photosensitive polyimide based on 5‐(2,5‐dioxotetrahydrofuryl)‐3‐methyl‐3‐cyclohexene‐1,2‐dicarboxylic anhydride

A negative type photosensitive polyimide with alicyclic moiety (NPI) was synthesized from 5‐(2,5‐dioxotetrahydrofuryl)‐3‐methyl‐3‐cyclohexene‐1,2‐dicarboxylic anhydride and 4,4‐diaminobenzophenone by one‐step polymerization in m‐cresol. Properties of the polyimides were characterized and a photo‐crosslinking mechanism was investigated using DEPT ¹³C‐NMR and FT‐IR spectroscopy. The negative polyimide showed good photosensitivity on exposure to UV light from a mercury xenon lamp. The polyimide showed remarkable solubility difference after photo‐ irradiation with an exposure dose of 500 mJ/cm². The resulting negative pattern of the photo‐cured NPI exhibited 10 μm resolution. Glass transition temperature of the photo‐crosslinked polyimide was about 307°C, which increased by 10°C compared to that of the polyimide before UV exposure. Transmittance of NPI after photo‐irradiation was about 87% at 500 nm. Copyright © 2004 John Wiley & Sons, Ltd.     

New Photosensitive High Temperature Polymers for Electronic Applications

A new photosensitive high temperature polymer stable up to 500%deg;C with high photosensitivity and high resolution has been developed. The trend toward a high degree of integration in solid-state technology requires the use of new high temperature photosensitive insulating materials. Toray's Photoneece system provides such versatile polyimide pattern-generation techniques, containing a unique photosensitive polyimide precursor which can be spun or coated on the substrate. The resultant relief of photosensitive polyimide precursor, after exposure to UV light with a mask, development, and cure processing, is transformed into a cyclized aromatic polyimide. The new system has higher photosensitivity and resolution and eliminates three steps in the conventional pattern-making process for integrated circuits, resulting in a significant cost reduction. The characterization of pattern generation, the conversion to polyimide patterns, and the properties of both Photoneece and the patterns are discussed.     

Photoinduced liquid crystal blue phase by bent-shaped cis isomer of the azobenzene doped in chiral nematic liquid crystal

A photoresponsive azobenzene molecule DCAZO2 with two cholesteryl groups linked to both sides of the azobenzene group is doped in a mixture of nematic liquid crystal E7 and chiral dopant S811 (61.9 wt% E7, 36.1 wt% S811 and 2.0 wt% DCAZO2). Cooled from isotropic phase to 33.0°C, chiral nematic liquid crystal (N*LC) was formed in the sample and then the temperature was kept unchanged at 33.0°C. UV light irradiation induces the trans–cis photoisomerisation and thus an obvious phase transition. When the azobenzene groups isomerise to a cis-saturated state, the UV light was turned off and the white light was turned on at the same time. The bent-shaped cis isomer then turns back to the planar trans isomer gradually. A blue–green platelet texture representing cubic blue phase (BP) was observed and the size of the platelets was increased along with the cis–trans isomerisation. UV–vis absorption spectra indicate that the photoinduced BP exists when the isomerisation degree is between 79% and 18%, and further cis–trans isomerisation change BP back into N*LC. The large geometric structure of the cholesteryl groups and the large bent angle θ of the cis isomer are supposed to be responsible for the interesting result.     

Recent Development of Advanced Functional Polymers for Semiconductor Encapsulants of Integrated Circuit Chips and High-temperature Photoresist for Electronic Applications

A new polymer system of semiconductor devices was studied in response to the multifunctional systems evolved. A variety of functional polymers have been developed in the manufacture of semiconductor and integrated circuit (IC) packaging devices by R&D of high-temperature polymers. With the increase in integration of electronic devices and the need to reduce overall size, market needs are moving to multilevel metallization. Toray's core polymer technologies for electronic devices in the past 35 years (1961–95) are reviewed. The new technology of IC encapsulants of biphenyl type epoxy compounds is described for the new generation 16 megabits dynamic randon accessory memory (DRAM) electronic memory device, with good heat dissipation characteristics and low stress with an anti-flammability UL V-0 property of halogen-free formulation. As core functions are built into devices, packaging and mount technologies become more important. A new photosensitive high-temperature polymer stable up to 500°C with photosensitivity and high resolution has been developed. The trend toward a high degree of integration in solid-state technology requires the use of new high-temperature photosensitive insulating materials. Toray's "Photoneece" system provides such versatile polyimide pattern-generation techniques, containing a unique photosensitive polyimide precursor which can be spun or coated on the substrate. The main components of polyimide consist of poly(amic acid), a tertiary amine having methacrloyl group and a sensitizer. Through analyses of visible, fluorescence and electron spin resonance (ESR) spectroscopy, and flash photolysis and quantitative analyses, a new reaction mechanism is proposed. By photo-irradiation, the stable ion radical is formed without vinyl radical polymerization. The polymer is excited to form an excited singlet state. An anion radical of pyromellitic diamide moiety in a polymer chain is generated after intersystem crossing to an excited triplet state. The resultant relief of the photosensitive polyimide precursor, after exposure to UV light with a mask, development and cure processing, is transformed into a cyclized aromatic polyimide. The new system has higher photosensitivity and resolution and eliminates three steps in the conventional pattern-making process for integrated circuits, resulting in a significant cost reduction. The characterization of pattern generation, the conversion to polyimide patterns, and the properties of both Photoneece and the patterns are discussed. Initial photoreaction of an ionic-bonded photosensitive polyimide was studied by fluorescence, ESR and flush photolysis. A charge transfer complex between a polyamic acid (polyimide precursor) and an aromatic amine (sensitizer) was formed by UV irradiation from fluorescence measurement. Photo-induced radical was observed by ESR measurement. The photo-induced radical was an anion radical of polyamic acid from flush photolysis. From these results, a new photo-induced charge separation in an ionic bonded photosensitive polyimide film was found. Photo-induced electron transfer from an aromatic amine (sensitizer) to acid part of the polyamic acid occurs. © 1997 John Wiley & Sons, Ltd.     

Phosphonylation of a polypentenamer and preparation of its hydrogenated derivatives

Phosphonylated derivatives of a polypentenamer (PP) containing 82% trans and 17% cis double bonds have been prepared by the free-radical addition of dimethylphosphite to the double bonds and subsequent hydrogenation of the residual unsaturation. In this way derivatives were prepared containing approximately 5 and 10 mole % dimethylphosphonate side groups. These side groups were further reacted by hydrolysis or neutralization to form phosphonic acid and cesium phosphonate salts. Reaction conditions were so chosen that no backbone degradation occurred, and side reactions leading to crosslinking were avoided. The derivatives were characterized by gel-permeation chromatography (GPC), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), infrared spectroscopy, and nuclear magnetic resonance spectroscopy. It was found that increasing substituent concentration decreases the melting point T_m in the case of the hydrogenated derivatives and increases the glass transition temperature T_g in the case of the unhydrogenated derivatives. The free acid derivatives are the least thermally stable of all those studied and the hydrogenated derivatives are generally more stable than the unhydrogenated derivatives.     

Mobility of the ring structure and the characteristics of crosslinked polymers: The structural effect of the eleven-membered ring and its homologs upon the dynamic mechanical properties and glass transition temperature of crosslinked diallyl succinate polymers

Dynamic mechanical properties and glass transition temperatures were measured for crosslinked polymers derived from diallyl succinate monomers. The mobility of the diester having an eleven-membered ring and of homologous structures which are introduced in the crosslinked polymer system, is discussed on the basis of the parameter for cyclization polymerization of a monomer, dynamic mechanical properties, and glass transition temperature. Control of the mobility of the ring structure and its homologous structures involved in the crosslinked polymers was attempted by modification of the substituent at the 1- or 1,2-position of diallyl succinate, and the diallyl succinate monomers were derived from the succinic acid and its derivatives: succinic acid, methyl succinic, ethyl succinic, and chlorosuccinic acids; cis-1,2-dicarboxylic acids of cyclopropane, cyclobutane, cyclopentane, and cyclohexane; cis-1,3- and 1,4-dicarboxylic acids of cyclohexane, and phthalic acid. The results obtained are explained well on the basis of the mobility of the ring and homologous structures.     

Synthesis and characterization of photosensitive polyimides from methylthiomethyl-substituted 4,4′-diaminodiphenylmethanes and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride

A series of novel polyimides are synthesized by the reaction of 3,3′,4,4′-benzophenonete-tracarboxylic dianhydride (BTDA) with four methylthiomethyl-substituted aromatic diamines: 3-methylthiomethyl-4,4′-diaminodiphenylmethane ( I ), 3,3′-dimethylthiomethyl-4,4′-diaminodiphenylmethane ( II ), 3,3′,5-trimethylthiomethyl-4,4′-diaminodiphenylmethane ( III ), and 3,3′,5,5′-tetramethylthiomethyl-4,4′-diaminodiphenylmethane ( IV ) in refluxing m-cresol. The polyimide of diamine I and BTDA carrying only one pendant methylthiomethyl group in a repeating unit is readily soluble in m-cresol, chloroform, and polar aprotic solvents. Increasing the number of the pendant group results in higher solubility. These fully imidized polyimides are also intrinsically photosensitive. The fraction of photoreactive benzophenone sites that relates to the rate and degree of completion of photocrosslinking reaction increases systematically with the increase of the pendant group content. As the average number of the pendant group in a repeating unit reaches 3, 63% of benzophenone sites are found to be photoreactive. These methylthiomethyl-substituted polyimides possess moderate tensile strength which falls in the range of 67–81 MPa. As a result of the increase of methylthiomethyl content, this type of polyimide reveals higher glass transition temperature but lower thermal stability due to the considerable dimension of the pendant group and the ready cleavage nature of the C? S bond. © 1993 John Wiley & Sons, Inc.