Reinforcement of polymers of 2,2 bis-4(2-hydroxy-3-methacryloyloxy propoxy) phenyl propane by ultra-high modulus polyethylene fibres.

A study has been made of the reinforcement of 2,2 bis-4(2 hydroxy-3-methacryloyloxy propoxy) phenyl propane/tetra-hydrofurfuryl methacrylate copolymers with ultra-high modulus polyethylene fibres. The fibres were orientated longitudinally, in loadings up to 50% w/w, and both untreated and surface treated fibres were studied. Modulii up to approximately 35 GPa were achieved in the axial direction, and the specimens could not be broken in the simple flexure test employed. Electron microscopy of fractured specimens showed extremely good contact between resin and fibre. No deterioration in properties was observed over 6 months in water.     

Study of polymeric systems based on 2,2 bis-4(2-hydroxy-3-methacryloyl-oxypropoxy) phenyl propane.

2,2 bis-4(2-hydroxy-3-methacryloyloxypropoxy) phenyl propane is the basic monomer for a large number of proprietary dental composite filling materials. In this paper, studies have been made of its copolymers with various comonomers. 2,2 bis-4(2-hydroxy-3-methacryloyloxypropoxy) phenyl propane--tetrahydrofurfuryl methacrylate copolymers, at about the 95/5% v/v level, showed an enhanced modulus over that of the test material itself, to give a Young's modulus of -4.8 GPa. This reflected an enhanced activation energy of the glass transition temperature, indicating a very specific free volume effect of the diluent monomer. Further studies 2,2 bis-4(2-hydroxy-3-methacryloyloxypropoxy) phenyl propane-tetrahydrofurfuryl methacrylate room temperature polymerized copolymers showed that enhanced modulus could be achieved by including in the system small amounts of inhibitor; 0.3% v/v 2,6 di-tertiary butyl phenol elevated the Young's modulus of a benzoyl peroxide--NN-dihydroxy ethyl p-toluidine cured system from 3.1 to 3.6 GPa. Such resins may be useful in improved dental fissure sealants and composite filling materials.     

Synthesis and characterization of new soluble polyimides derived from 2,2-bis[3,5-dimethyl-4-(4-aminophenoxy)phenyl]propane

A diamine monomer containing isopropylidene and methyl substituted arylene ether, 2,2-bis[3,5-dimethyl-4-(4-aminophenoxy)phenyl]propane (TBAPP), was prepared in two steps. The monomer was reacted with six different aromatic tetracarboxylic dianhydrides in N,N-dimethylacetamide (DMAc) to obtain the corresponding new polyimides via the poly(amic acid) precursors and thermal or chemical imidization. The poly(amic acid)s obtained had inherent viscosities ranging from 1.38–2.10 dL · g⁻¹. All the poly(amic acid)s could be cast from DMAc solutions and thermally converted into transparent, flexible, and tough polyimide films. The polyimide films had a tensile strength in the range from 52–95 MPa, an elongation at break within a range of 4–8%, and a tensile modulus in the range from 1.60–2.09 GPa. All polyimides were amorphous. The polyimides derived from diamine TBAPP had excellent solubility in various solvents except for those derived from rigid dianhydrides such as pyromellitic dianhydride and 3,3′,4,4′-biphenyltetracarboxylic dianhydride. These polyimides showed glass transition temperatures between 249–293°C and decomposition temperature at 10% mass loss temperatures ranging from 460–485°C in nitrogen.     

Liquid crystal polymers containing macroheterocyclic ligands, 7. Synthesis and characterization of 4-[(4-methacryloyloxy)-undecyloxy-2-methylphenylethynyl]phenyl (benzo-15-crown-5)-4′-carboxylate

The synthesis and thermal characterization of 4-[(4-methacryloyloxy)undecyloxy-2-methyl-phenylethynyl]phenyl (benzo-15-crown-5)-4′-carboxylate ( 8 ) and of poly( 8 ) are described. 8 exhibits monotropic nematic and smectic mesophases, while poly( 8 ) shows enantiotropic nematic and smectic mesophases. In spite of its very long flexible spacer, poly( 8 ) does not display sidechain crystallization.     

Synthesis and characterization of new polyamides and polyimides prepared from 2,2-bis[4-(4-aminophenoxy)phenyl]adamantane

In this work, we synthesized a new diamine containing a pendant adamantane group and a flexible aryl ether unit, 2,2-bis[4-(4-aminophenoxy)phenyl]adamantane ( BAPA ) in three steps starting from 2-adamantanone. A series of new polyamides having inherent viscosities of 0.72–0.90 dL·g^–1 were prepared by direct polycondensation with aromatic dicarboxylic acids using triphenyl phosphite and pyridine as condensing agents. All polymers revealed an amorphous nature and were almost readily soluble in a variety of polar solvents. The glass transition temperature of these polyamides range from 254–294°C. The polyamides remain fairly stable up to a temperature around 450°C and lose 10% weight between 490 and 524°C in nitrogen atmosphere. A series of new polyimides were also synthesized from BAPA and various aromatic tetracarboxylic dianhydrides by the conventional two-step method. The inherent viscosities of polyimides were in the range of 0.66–0.77 dL·g^–1. The polyimides are amorphous and have glass transition temperatures between 276 and 310°C. Thermogravimetric analyses demonstrated that almost all polymers are stable up to 450°C, and the 10% weight loss temperatures were recorded in the range of 515 to 541°C in nitrogen.     

(9-[4-acetyl-3-hydroxy-2-n-propylphenoxy) methyl]-3-(1H-tetrazol-5-yl)-4H-pyrido [1,2-a] pyrimidin-4-one), AS-35, inhibits leukotriene synthesis

AS-35, (9-[4-acetyl-3-hydroxy-2-n-propylphenoxy) methyl]-3-(1H-tetrazol-5-yl)-4H-pyrido[1, 2-a] pyrimidin-4-one), was developed as a leukotriene (LT) receptor antagonist, which also inhibited IgE-mediated release of leukotrienes (LTs). We have investigated the action of AS-35 on the enzyme activities which are involved in the synthesis of LTC(4) and LTB(4) (LT-synthesizing enzymes); cytosolic phospholipase A(2) (cPLA(2)), 5-lipoxygenase (5-LO), leukotriene (LT)C(4) synthase and LTA(4) hydrolase. AS-35 dose-dependently inhibited IgE- and A23187-stimulated production of LTC(4) by up to 71.5-84.8% and that of LTB(4) by 48.3-49.2% at 2. 5x10(-5) M. The assays for cPLA(2)(-), 5-LO-, LTC(4) synthase- and LTA(4) hydrolase-activities revealed that the inhibition is attributable to suppression of cPLA(2), 5-LO and LTC(4) synthase but not LTA(4) hydrolase. We have also studied the action of AS-35 on the release of beta-hexosaminidase (beta-HEX) as a marker of preformed mediators. AS-35 had only weak inhibitory action on the release of beta-HEX. The results indicate that anti-allergic action of AS-35 is predominantly attributable to its inhibition of LT synthesis by suppressing three consecutive enzymes for LTC(4) synthesis.     

Synthesis and polymerization of epoxymethacrylates, 1. Catalysis and kinetics of the addition reaction of methacrylic acid and 2,2-bis[4-(2,3-epoxypropoxy)phenyl]propane

The kinetics of the addition reaction of methacrylic acid (1) and 2,2-bis[4-(2,3-epoxypropoxy)-phenyl]propane catalyzed by tertiary aliphatic amines, aromatic N-heterocycles and quaternary ammonium salts, respectively, was studied in bulk with equimolar amounts of functional groups from room temperature to 120°C. A reaction order of 1,5 with regard to the conversion of epoxy as well as carboxylic groups was observed. This can be explained assuming the formation of an ammonium alkoxide ion pair by the equilibrium reaction of an epoxy group with ammonium carboxylate and the irreversible consecutive reaction of the ion pair with (1) under formation of 2-hydroxyester groups and regeneration of ammonium carboxylate. The reaction rate constants increase linearly with the concentration of the catalyst and increase with increasing basicity of alkylpyridines. The advantage of the aromatic N-heterocyclic catalysts consists in their stability to peroxides which are ingredients of preparations together with the epoxy methacrylate Bis-GMA, e. g. in dental composites and adhesives.     

1-[4-Fluoro-2-(2-nitrovinyl)phenyl]pyrrolidine Suppresses Toll-Like Receptor 4 Dimerization Induced by Lipopolysaccharide

Toll-like receptor 4 (TLR4) recognizes LPS and triggers the activation of the myeloid differential factor 88 (MyD88)- and toll-interleukin-1 receptor domain-containing adapter, inducing interferon-β (TRIF)-dependent major downstream signaling pathways. Previously, we presented biochemical evidence that 1-[4-Fluoro-2-(2-nitrovinyl)phenyl]pyrrolidine (FPP), which was synthesized in our laboratory, inhibits NF-κB activation induced by LPS. Here, we investigated whether FPP modulates the TLR4 downstream signaling pathways and what anti-inflammatory target in TLR4 signaling is regulated by FPP. FPP inhibited LPS-induced NF-κB activation by targeting TLR4 dimerization. These results suggest that FPP can modulate the TLR4 signaling pathway at the receptor level to decrease inflammatory gene expression.     

Mass spectrometric characterization of a 2,2-bis[4-(2,3-epoxypropoxy)phenyl]propane-aniline addition polymer and its telechelic prepolymers

Fast-atom bombardment (FAB) and plasma desorption mass spectrometry of high molecular weight addition polymers of 2,2-bis[4-(2,3-epoxypropoxy)phenyl]propane (DGEBA) and aniline show protonated molecular ions of the intact polymer and oligomer molecules. The oligomeric products consist mainly of cyclooligomers. Their formation can be observed during the polymerization reaction. Telechelic prepolymers having epoxide end groups as well as telechelics containing amino end groups were found with lower degree of polymerization in the mass spectra. Side reactions such as ether formation or epoxide polymerization were not observed. Telechelic DGEBA-aniline prepolymers are shown to consist of a series of oligomers as shown by highpressure liquid chromatography (HPLC) analyses. Consequently, the FAB mass spectra of the prepolymers show molecular ions of the different oligomers. Furthermore, under the conditions of the FAB mass spectrometric analysis fragmentation of the prepolymers to iminium fragment ions was observed.     

In vitro drug release studies of 2-hydroxyethyl acrylate or 2-hydroxypropyl methacrylate-4-{(1E,4E)-5-[4-(acryloyloxy)phenyl]-3-oxopenta-1,4-dienyl}phenyl acrylate copolymer beads

4-{(1E,4E)-5-[4-(Acryloyloxy)phenyl]-3-oxopenta-1,4-dienyl}phenyl acrylate (APPA) was synthesized by reacting (1E,4E)-1,5-bis(4-hydroxyphenyl)penta-1,4-dien-3-one (HPD) and acryloyl chloride using triethylamine as a base. 2',4-Dichloro-5'-fluoro-1-ene-2-(4-hydroxyphenyl)phenone (EHP) (Arun A, Reddy BSR, Rajkumar M. Polymeric drug for antimicrobial activity studies: Synthesis and characterization. J Bioact Compat Polym 2003;18:219) was used for the controlled release studies. Two types of porous hydrogels were prepared by copolymerizing 2-hydroxyethyl acrylate (HEA) or 2-hydroxypropyl methacrylate (HPMA) with APPA (as a crosslinker) by employing the suspension polymerization technique. The morphology of the hydrogels were characterized by the optical microscopy (OM) and scanning electron microscopy (SEM). Different variations were employed in the preparation of hydrogels to study the effect of crosslinker percentage and drug the loading percentage. Totally 18 types of hydrogels were prepared. The drug-releasing pattern was monitored over a period of 4 weeks using the UV spectroscopic technique by measuring the absorptions at 330.5 nm. In vitro release experiments were carried out at pH 7.4 and pH 9.2. In total, 36 releasing experiments were conducted. The results showed that the controlled release of the drug was dependent on the monomer (HEA or HPMA), crosslinker percentage (CLP), drug-loading percentage (DLP), and pH. The release rate was higher for HEA-based hydrogels when compared with HPMA-based hydrogels in all compositions. The release rate was noticeably higher in pH 9.2 than pH 7.4.     

Synthesis and physico-chemical properties of poly[4-(1,1,3,3-tetramethylbutyl)phenyl methacrylate]

Poly[4-(1,1,3,3-tetramethylbutyl)phenyl methacrylate] ( 1a ) was synthesized and its physicochemical properties were determined in the condensed phase and in dilute solution. The polymerization of 4-(1,1,3,3-tetramethylbutyl)phenyl methacrylate was carried out by radical mechanism in solution with 2,2′-azoisobutyronitrile as initiator. Several samples were characterized by their intrinsic viscosity, by osmometric measurements, differential scanning calorimetry, and X-ray diffraction. The viscometric behaviour of fractions of 1a was studied in good solvents and theta solvents, and the conformational parameters were calculated. Polymer 1a presents an unusual high rigidity in the chain. X-Ray diffraction of this polymer indicates a one-dimensional ordering of a mesomorphic type.     

Induction of gastrointestinal tract nuclear anomalies in B6C3F1 mice by 3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]-furanone and 3,4-(dichloro)-5-hydroxy-2[5H]-furanone, mutagenic byproducts of chlorine disinfection

Two chlorinated hydroxylated furanones, 3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]-furanone (MX) and 3,4-(dichloro)-5-hydroxy-2[5H]-furanone (MA), are bacterial mutagens and they are also byproducts of chlorine disinfection, and frequent contaminants of drinking water. In this work MX is shown to induce nuclear anomalies in the gastrointestinal tract of the B6C3F1 mouse. The other chlorohydroxy-furanone, MA, gives suggestive evidence of activity. In this bioassay MX was approximately equivalent in potency to epichlorohydrin (ECH) but was much less potent than methylnitrosourea (MNU). The latter two chemicals are confirmed rodent gastrointestinal tract carcinogens. The duodenum was the most sensitive tissue responding with both increased numbers of nuclear anomalies per mouse and increased incidence of animals presenting the nuclear aberrations 24 hr after a single oral dose of 0.37 mmol/kg-1 of MX. MA also induced a significant increase in duodenal nuclear anomalies, but only at the highest dose (0.46 mmol/kg-1). The proximal colon and forestomach responded to MX but not MA. This is the first study demonstrating that chlorohydroxyfuranones are capable of inducing nuclear toxicity in vivo. However, it is clear, for MX at least, that its potency in the gastrointestinal tract nuclear anomalies assay is not commensurate with its extreme bacterial mutagenicity. Since the gastrointestinal tract tissues are directly exposed to orally administered genotoxins, one possible explanation for the weak response observed in this study could be that mammalian cells can effectively detoxify chlorohydroxyfuranones.     

Synthesis and characterization of new cardo polyamides derived from 8,8-bis[4-(4-aminophenoxy)phenyl]tricyclo[5.2.1.02,6]decane

A series of novel cardo polyamides were prepared by direct polycondensation of 8,8-bis[4-(4-aminophenoxy)phenyl]tricyclo[5.2.1.0^2,6]decane and various aromatic dicarboxylic acids in N-methyl-2-pyrrolidinone (NMP) using triphenyl phosphite and pyridine as condensing agents. The polymers were produced with high yield and moderate to high inherent viscosities of 0.71–1.40 dL·g^–1. Nearly all the polymers could be readily dissolved in polar aprotic solvents such as NMP, N,N-dimethylacetamide (DMAc) and N,N-dimethylformamide, dimethyl sulfoxide as well as less polar solvents such as pyridine and γ-butyrolactone. The polymers were solution-cast from DMAc solution into transparent, flexible, and tough films which were further characterized by X-ray and mechanical analysis. Nearly all the polymers were amorphous, and the polyamide films had a tensile strength range of 97–111 MPa, an elongation at break range of 9–11%, and a tensile modulus range of 1.9–2.3 GPa. The polyamides had glass transition temperatures between 251–272°C and 10% weight loss temperatures in the range of 468–490 and 499–532°C in nitrogen and air atmosphere, respectively.     

Mutagenicity of two 2-phenylbenzotriazole derivatives, 2-[2-(acetylamino)-4-(diethylamino)-5-methoxyphenyl]-5-amino- 7-bromo-4-chloro-2H-benzotriazole and 2-[2-(acetylamino)-4-(diallylamino)-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole and their detection in river water in Japan

We recently detected five 2-phenylbenzotriazole (PBTA)-type mutagens (PBTA-1, PBTA-2, PBTA-3, PBTA-4 and PBTA-6) in concentrates from several rivers that flow in geographically different areas in Japan containing textile-related industries. On the basis of synthesis studies, these five PBTA derivatives were deduced to have originated from the corresponding dinitrophenylazo dyes, which are industrial chemicals used in textile dyeing, via reduction and chlorination. 2-[(2-Bromo-4,6-dinitrophenyl)azo]-5-(diethylamino)-4-methoxyacetanilide (Color Index name Disperse Blue 291, CAS registry no. 56548-64-2) and 2-[(2-bromo-4,6-dinitrophenyl)azo]-5-(diallylamino)-4-methoxyacetanilide (Color Index name Disperse Blue 373, CAS registry no. 51868-46-3) are used in textile dyeing and have 2-[(2-bromo-4,6-dinitrophenyl)azo]-4-methoxyacetanilide moieties in their structures, which are thought to be essential for their conversion to mutagenic PBTA derivatives. In the present study we have synthesized 2-[2-(acetyl-amino)-4-(diethylamino)-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-7) and 2-[2-(acetylamino)-4-(diallylamino)-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-8) from Disperse Blue 291 and Disperse Blue 373, respectively, by reduction with iron powder and subsequent chlorination with sodium hypochlorite. Both PBTA-7 and PBTA-8 exerted strong mutagenicity in Salmonella typhimurium TA98 and YG1024 in the presence of S9 mix (43 000 and 1 430 000 revertants/nmol for PBTA-7 and 40 700 and 2 213 000 revertants/nmol for PBTA-8 in TA98 and YG1024). To clarify whether PBTA-7 and PBTA-8 exist in the environment, water samples were collected at seven sites in six rivers flowing through two different regions where textile dyeing industries are located. All water samples were mutagenic in Salmonella typhimurium YG1024 with S9 mix and their potencies ranged from 108 000 to 1 990 000 revertants/g blue rayon. PBTA-7 and PBTA-8 were detected in water samples from both regions at levels of <0.1-101.4 ng/g blue rayon and <0.1-48.9 ng/g blue rayon, respectively. In some samples PBTA-7 and PBTA-8 could contribute up to 15% of the water mutagenicity.     

Conformational transition in poly[4-(1,1,3,3-tetramethylbutyl)phenyl methacrylate] and poly(4-tert-butylphenyl methacrylate) in dilute solutions

Temperature dependence of viscosity data and refractive index increment was investigated on two polymers: poly[4-(1,1,3,3-tetramethylbutyl)phenyl methacrylate] ( 1a ) and poly(4-tert-butylphenyl methacrylate) ( 1b ) in dilute solution. A discontinuity in intrinsic viscosity was observed over a narrow temperature range. From this behaviour it was possible to visualize sharp changes of unperturbed dimensions (K_θ) and thermodynamic parameters (B). This phenomenon can be accounted for by assuming conformational changes of the chain in the chosen solvent in a specific temperature range. These changes can be also observed by discontinuities in refractive index increments dn/dc. In the case of 1b the conformational change disappears on addition of a polar solvent (CHCl₃).     

Thermal treatment of poly[ethylene-alt-2,2-bis(1,4-phenylene)propane carbonate]: A reinvestigation

The final product of the thermal treatment of poly[ethylene-alt-2,2-bis(1,4-phenylene)-propane carbonate] (polymer 1 ) at 280°C under vacuum was characterized as a random copolymer containing both ether and carbonate groups and not as pure bisphenol A polycarbonate as reported previously by other authors. Infrared and NMR spectroscopy were used to detect the changes of the polymer structure during the thermal treatment; the resulting polymers were also characterized by measuring their intrinsic viscosity. During the thermal treatment different reactions occur: exchange reactions (which would lead to a random copolycarbonate), and intramolecular elimination of ethylene carbonate and carbon dioxide. This last elimination is responsible for the formation of ether groups which, being stable under the reactions conditions, prevent the complete elimination of the aliphatic moieties. The final random copolymer was also prepared by reacting pure bisphenol A polycarbonate (PC) and ethylene carbonate; this confirms the occurrence of exchange reactions, which lead to a random copolycarbonate having a structure similar to the polymer deriving from polymer 1 . Surprisingly, in the presence of a typical exchange reaction catalyst such as dibutyltin dimethoxide or titanium tetrabutoxide, the final product of the thermal treatment of polymer 1 is pure PC.     

Polymerization of bis[4-bis(2,3-epoxypropyl)aminophenyl]methane. Identification of new derivatives of 3-hydroxy-1,2,3,4-tetrahydroquinoline

Bis[4-bis(2,3-epoxypropylamino)phenyl]methane ( 3 ) was shown to undergo homopolymerization when heated without or with an accelerator such as N,N-dimethylbenzylamine ( 10 ). When 3 was polymerized without accelerator, no ether formation was found. A new type of curing process involving opening of the epoxy ring by reaction at the phenyl ring in ortho position to the tertiary amino substituent allows one to explain the formation of compounds containing the 3-hydroxy-1,2,3,4-tetrahydroquinoline moiety. The corresponding derivatives 4–7 were isolated for the first time and their structures established by different spectroscopic methods such as ¹H, ¹³C, 2D δ-δ NMR, and FT-IR. Intermolecular reaction at the orthocarbon of the tertiary amino group with an epoxy group may explain the resin formation by curing 3 without accelerator. Polymerization of 3 with accelerator 10 led to polyetherification. This result may be explained in terms of difference in the reactivity of the tertiary amines 3 and 10 towards the epoxy group. The former gives an unstable “zwitterion” by reaction at the nucleophilic carbon, subsequently leading to the stable hydroquinoline system by proton transfer. The latter also gives an unstable “zwitterion” by reaction at the nucleophilic nitrogen, however, it induces epoxy ring-opening polymerization due to the lack of intramolecular stabilization. Moreover, the results suggest that the hydroxyl functions, formed in the absence of an accelerator, do not react with epoxides under the studied conditions.     

3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone [MX] shows initiating and promoting activities in a two-stage BALB/c 3T3 cell transformation assay

A transformation assay using BALB/c 3T3 cells was conducted on 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) to assess initiation and promotion activities of MX carcinogenesis. Statistically significant positive responses were obtained compared with the corresponding solvent controls in both the initiation assay post-treated with 12-O-tetradecanoylphorbol 13-acetate (TPA) and the promotion assay pretreated with 3-methylcholanthrene (MCA). Both TPA and MX inhibited metabolic cooperation in an assay using co-culture of V79 6-thioguanine (6-TG) sensitive and insensitive cells. However, cells isolated from transformed foci in the initiation assay did not induce any nodules after inoculation to BALB/c mice, the strain of mouse from which the transformation assay cells were derived. Although the study was carried out for 2-3 weeks, this might have been too short to develop nodules under the conditions of this experiment. This in vitro cell transformation study with MX adds supportive information to studies showing MX carcinogenicity and tumour promoter activity, and adds mechanistic understanding of the action of MX.     

Liquid-crystalline polymers containing heterocycloalkanediyl groups as mesogens, 6. Liquid-crystalline poly[trans-11-{4-[5-(4-methoxyphenyl)-1,3-dioxan-2-yl]-2,6-dimethylphenoxy}undecyl methacrylate] and poly[trans-11-{4-[5-(4-methoxyphenyl)-1,3-dioxan-2-yl]-2,6-dimethylphenoxy}undecyl acrylate]

The synthesis and characterization of poly[trans-11-{4-[5-(4-methoxyphenyl)-1,3-dioxan-2-yl]-2,6-dimethylphenoxy}undecyl methacrylate] and poly[trans-11-{4-[5-(4-methoxyphenyl)-1,3-dioxan-2-yl]-2,6-dimethylphenoxy}undecyl acrylate] is presented. Both polymers exhibit nematic mesophases and do not present side-chain crystallization. At temperatures higher than 160°C the 1,3-dioxane-2,5-diyl groups undergo a thermally induced trans-cis isomerization. A radical mechanism is proposed for this isomerization.