Synthesis and characterization of novel aliphatic polycarbonates

A new six‐membered cyclic carbonate monomer, 5‐benzyloxy‐trimethylene carbonate, was synthesized from 2‐benzyloxy‐1,3‐propanediol, and the corresponding polycarbonate, poly(5‐benzyloxy‐trimethylene carbonate) (PBTMC), was further synthesized by ring‐opening polymerization in bulk at 150 °C using aluminum isobutoxide [Al(OⁱBu)₃], aluminum isopropoxide, or stannous octanoate as an initiator. The results showed that a higher molecular weight polycarbonate could be obtained in the case of Al(OⁱBu)_3. The protecting benzyl group was removed subsequently by catalytic hydrogenation to give a polycarbonate containing a pendant hydroxyl group (PHTMC). The polycarbonates obtained were characterized by Fourier transform infrared spectroscopy, ¹H NMR,¹³C NMR, gel permeation chromatography, and DSC. NMR results of PBTMC offered no evidence for decarboxylation occurring during the propagation. The pendant hydroxyl group in PHTMC resulted in an enhancement of the hydrophilicity of the polycarbonate. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 70–75, 2002     

Synthesis of phosphorus-based flame retardant systems and their use in an epoxy resin

Methods are proposed to synthesize efficient organophosphorous compounds and combine them with montmorillonite nanoparticles. The chemical-physical structure and mechanism of action of the new systems were studied in epoxy resin. Best results were achieved using the fully phosphorylated calixresorcinarene derivative: the heat release rate peak could be decreased by 61% and the LOI value was increased from 21 to 28. The salt form of additives in case of phosphorylated phloroglucine derivatives was not advantageous in epoxy resin, because the additives could not participate in the crosslinking process effectively due to their inhomogenous distribution in the matrix. The incorporation of the nanoparticles did not create the desired flame retardant effect which can be explained by the increased heat conductivity and lower mobility of the nanoparticles due to the crosslinked structure.     

Synthesis and characterization of novel multifunctional epoxy resin

A novel multifunctional epoxy resin was synthesized by polyphenol and epichlorohydrin.The structure and molecular weight ofthe multifunctional epoxy were characterized by FTIR and ESI-MS.DSC and DMTA were used to investigate the thermal propertyof multifunctional epoxy cured by DDS.The thermal resistance of the synthesized multifunctional epoxy was much better than astandard diglycidyl ether of bisphenol-A epoxy.     

Synthesis of a novel class of chromophoric cross-linkers

Considering the special place of aromatic diazo compounds in photo-responsive materials and growing demand for materials with interesting optical properties, a new class of chromophoric cross-linkers was synthesized by acrylation of diazo derivatives of m-diaminobenzene. The cross-linkers are soluble in a wide variety of organic solvents as well as in mixtures of water and water miscible solvents. The chromophores of the cross-linkers are stable in protic and some certain aprotic solvents and remain stable after cross-linking. The chemical structure of this class allows one to have a cross-linker with tuned chemical reactivity and solubility with post-linking applicability. The cross-linkers are obtained from reactions with simple chemistry in high yields and are able to participate in radical and ionic polymerization as well as in nucleophilic addition reactions. Successful participation of these substances in acrylamide polymerization and sol–gel preparation is demonstrated.     

Synthesis and characterization of UV-curable polydimethylsiloxane epoxy acrylate

UV-curable polydimethylsiloxane epoxy acrylate (PSEA) was synthesized by hydrosilylation of allyl glycidyl ether with hydrogen-containing polydimethylsiloxane to give polydimethylsiloxane-type epoxy resin which modified with acrylic acid. The curing speed and the double bond conversion in the UV cured film were influenced by the purity of PSEA with Fourier transform infrared spectroscopy (FT-IR) measurements. The influences of the synthetic process, such as, the reaction temperature, the concentration of reactants and the catalyst which determined the purity and activity of resins were discussed in detail. The structures of this resin were characterized by ¹H-NMR and FT-IR spectra. The molecular weight was checked by gel permeation chromatography, and M_n is 45,000. The properties of the cured film were also investigated by thermogravimetric analyzer, dynamical thermal mechanical analysis, and etc. For example, tensile strength (6.9 Mpa), elongation (20%), hardness (A; 18), water absorption (24 h; 2%), weight loss (40 min, 300 °C; 5%) and etc.     

Synthesis and characterization of functional aliphatic copolyesters

Functional aliphatic copolyesters of succinic acid (SA) and citric acid (CA) were synthesized via direct copolycondensation in the presence of 1,4‐butanediol, with titanium(IV) butoxide as a catalyst. The effects of the comonomer and comonomer ratio on the polycondensation and the melting and glass‐transition temperatures were investigated. The melting temperature was very sensitive to the molar ratio of the SA–CA comonomer units. The chain extension of this poly(butylene succinate citrate) was carried out with hexamethylene diisocyanate. The intrinsic viscosity, crystallinity percentage, and rheological properties of these copolyesters were also studied. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3232–3239, 2002     

Synthesis and characterization of a novel,fluoride‐releasing dimethacrylate monomer and its dental composite

A novel, fluoride‐releasing dimethacrylate monomer containing zirconium fluoride chelate for use in dental composites was synthesized by an efficient four‐step procedure starting from 4,4‐bis‐(4‐hydroxyphenyl)‐pentanoic acid and was characterized by electrospray mass spectrometry, Fourier transform infrared (FTIR), and ¹H and ¹³C NMR spectroscopies. The synthesized monomer was photopolymerized with camphorquinone and 1‐phenyl‐1,2‐propane‐dione as initiators and N,N‐dimethylaminoethyl methacrylate as an accelerator. The photopolymerization process was investigated by FTIR spectroscopy. The experimental composite containing 13.7 wt % of the synthesized monomer was tested for fluoride release, fluoride recharge, compressive strength, and flexure strength, each in comparison to three commercial flowable dental composites. The results showed that the experimental composite had significantly higher fluoride release and fluoride recharge capabilities than the commercial flowable composites. The flexure strength was comparable to the commercial materials. The water sorption and solubility met the requirements of the International Organization for Standardization 4049 and the American National Standards Institute/American Dental Association Specification Number 27. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 985–998, 2004     

Synthesis and characterization of novel fully aliphatic polyimidosiloxanes based on alicyclic or adamantyl diamines

A series of fully aliphatic polyimidosiloxanes (APISiO) were prepared by poly(addition/condensation) reaction of bicyclo [2,2,2] oct‐7‐ene‐2,3,5,6‐tetracarboxylic dianhydride or cyclobutane‐1,2,3,4‐tetracarboxylic dianhydride and varying compositions of 1,3‐bis (3‐amino propyl)‐tetra methyl disiloxane and rigid adamantyl diamines (1,3‐diaminoadamantane or 3,3′‐diamino‐1,1′‐diadamantane) or flexible alicyclic diamines (4,4′‐methylene bis(cyclohexylamine) or 4,4′‐methylene bis(2‐methylcyclohexylamine)). High temperature one‐step synthesis in m‐cresol was employed to obtain APISiOs with intrinsic viscosity in the range of 0.28–0.59 dL/g. The final materials were characterized by ¹H and ¹³C NMR, ²⁹Si‐MAS‐NMR and IR spectroscopic analysis, thermogravimetric and differential scanning calorimetric analysis, and wide angle X‐ray diffractometry. UV–visible spectra revealed the optical behavior of the polyimides. It was found that the APISiOs containing appropriate ratio of adamantyl moieties together with flexible aliphatic siloxane groups exhibit good thermal and mechanical stabilities, solubility, fair transparency, and low dielectric constant (2.4–2.7). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5254–5270, 2006     

Synthesis and characterization of a novel cycloaliphatic epoxy resin starting from dicyclopentadiene

A novel tri-functional cycloaliphatic epoxy resin was synthesized starting from dicyclopentadiene. The chemical structures of the resultant epoxy resin and its precursor were characterized with FTIR spectroscopy, EEW, ¹H NMR and Mass spectrographic analyses. The thermal and mechanical properties of the resulting polymer were evaluated with differential scanning calorimeter (DSC), thermo-gravimetric and thermal mechanical analysis. Compared to that of the common cycloaliphatic epoxy resin ERL-4221, the cured polymer of the novel epoxy resin exhibited lower thermal degradation temperature with much higher char yield and similar thermal expansion coefficient. These excellent overall performances make it a promising packaging material.     

Linear aliphatic polysulfides: Synthesis and characterization

Binary condensation copolymers of 1,2-ethane dithiol and 1,3-propane dibromide, 1,4-butane dibromide, and 1,6-hexane dibromide were prepared. Yields ranged from 55 to 89% with molecular weights of 1–2 × 10⁴ Daltons. The polymers were synthesized via an S_N2 process with and without the presence of water. The polymers were characterized by DSC, viscosity, FT-IR, and ¹H-and ¹³C-NMR spectra.     

Synthesis and thermal properties of silicon-containing epoxy resin used for UV-curable flame-retardant coatings

A novel silicon-containing trifunctional cycloaliphatic epoxide resin tri(3,4-epoxycyclohexylmethyloxy) phenyl silane (TEMPS) was synthesized and characterized by FTIR, ¹H NMR, ¹³C NMR, and ²⁹Si NMR spectroscopic analysis. A series of flame-retardant formulations by blending TEMPS with a commercial epoxide resin DGEBA (EP828) in different ratios were prepared, and exposed to a medium pressure lamp to form the cured films in the presence of diaryliodonium hexafluorophosphate salt as a cationic photoinitiator. The thermal degradation behaviors of the cured films were evaluated by thermogravimetric analysis. The char yields under nitrogen and air atmospheres increased along with the TEMPS content. The limiting oxygen index (LOI) value increased from 22 for EP828 to 30 for TEMPS80, demonstrating the improved flame retardancy. The data from the dynamic mechanical thermal analysis showed that TEMPS had good miscibility with EP828. The T _s and T _g both decreased from 93 and 138 to 78 and 118 °C, respectively. The crosslinking density (ν _e) increased along with the TEMPS content. The mechanical property measurements indicated that the addition of TEMPS led to a decrease in the tensile strength and an increase in the elongation-at-break.     

Synthesis and characterization of novel chiral diporphyrins and their dimetal complexes

Reaction of chiral 2,2'-biamino-1,1'-binaphthalene (R or 5) with monosubstituted porphyrin 1b and 2b-c afforded novel chiral diporphyrins 3a-c and 4a-c. Their dimetal complexes [(M)2DiPor] have also been prepared. Both structures have been identified by MS, IR, UV-visible, 1H NMR spectra and elemental analysis. These novel chiral compounds show very high optical activities.     

Synthesis and characterization of benzodioxinone mono-telechelics and their use in block copolymerization

Poly(methyl methacrylate) (PMMA) and poly(ethylene glycol) methyl ether (mPEG)-based monotelechelics were quantitatively prepared by copper (I)-catalyzed azide/alkyne cycloaddition (CuAAC) click reactions using azido-terminated polymers and alkyne functional benzodioxinones. The monotelechelic containing dimethyl moities (2,2-dimethyl-5-(prop-2-yn-1-yloxy)-4H-benzo[d][1,3]dioxin-4-one) was heat-sensitive, whereas the monotelechelic containing diphenyl moieties (2,2-diphenyl-5-(prop-2-yn-1-yloxy)-4H-benzo[d][1,3]dioxin-4-one) was UV light sensitive. Based on the FT-IR, ¹H-NMR, and GPC investigations, the CuAAC click reactions enable the quantitative syntheses of monotelechelics under mild conditions. Moreover, the photosensitive mPEG-based monotelechelic was further utilized for the block copolymer synthesis upon UV-light irradiation. The photoinduced acylation of mPEG monotelechelic consist of (2,2-diphenyl-5-(prop-2-yn-1-yloxy)-4H-benzo[d][1,3]dioxin-4-one) in the presence of hydroxy-terminated poly(epsilon caprolactone) enabled the successful block copolymer formation.     

Synthesis and characterization of novel biodegradable aliphatic poly(ester amide)s containing cyclohexane units

Polyesters provide a good basis to work on for designing novel biodegradable materials that are also mechanically and thermally resistant. In this study, a series of aliphatic poly(ester amide)s (PEA) based on cyclohexane units was synthesized. Block‐copolymers of cyclohexyl sebacate and cyclohexyl sebacamide were produced by controlling the length of the ester block and the amount of amide during a two‐step melt/interfacial polycondensation reaction. Films produced from these materials could retain their shape above 373 K due to the physical network of amide hydrogen‐bonding. Thermal properties were also evaluated, with various melting and softening points obtained depending on the PEA composition. The determining factor for mechanical properties was the amount of amide introduced, with films containing up to 10 mol % amide showing the best handleability and flexibility. Tensile properties typical of an amorphous viscoelastic material were observed, but with much superior elongation to break achievable (～1700%). These materials were also shown to be hydrolyzable, noncytotoxic, and favorable for cell attachment: they may therefore have a promising future in the area of medical devices or packaging, especially as their properties can be tuned by changing their composition. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1785–1795, 2006     

Quinone-amine polymers. XII. Synthesis and characterization of novel polymers from 2-phenylbenzoquinone and aliphatic diamines

In order to study the effect of the presence of phenyl groups in poly (amino-quinone) (PAQ) polymers, several novel poly(amino-2-phenylbenzoquinone) (PhPAQ) polymers have been prepared from 2-phenylbenzoquinone and aliphatic diamines, such as 1,6-diaminohexane, 1,8-diaminooctane, 1,12-diaminodod+++++, and 1,4-diaminocyclohexane. Prior to the polymerization, 2-phenylbenzoquinone was generated in situ from 2-phenylhydroquinone in the presence of calcium hypochlorite as the oxidizing agent in dichloromethane. All of the polymers synthesized have been characterized with respect to their corresponding model compounds. It was also found that unlike their analogous PAQ polymers, PhPAQ polymers were highly soluble in many common organic solvents because of the presence of phenyl groups in their polymer backbone. © 1994 John Wiley & Sons, Inc.     

Synthesis, characterization and degradability of the novel aliphatic polyester bearing pendant N-isopropylamide functional groups

The synthesis, characterization, and degradability of the novel aliphatic polyester bearing pendant N-isopropylamide functional group are reported for the first time. 2-(N-Isopropyl-2-carbamoylethyl)cyclohexanone (CCH) was first synthesized by the Michael reaction of N-isopropylacrylamide with cyclohexanone and was subsequently converted into 6-(N-isopropyl-2-carbamoylethyl)-?-caprolactone (CCL) by the Baeyer-Villiger oxidation reaction using 3-chloroperoxybenzoic acid (mCPBA) as the oxidant. Finally, the novel functionalized poly(?-caprolactone) bearing the pendant N-isopropylamide functional groups, poly(6-(N-isopropyl-2-carbamoylethyl)-?-caprolactone-co-?-caprolactone)s (poly(CCL-co-CL)), were carried out successfully by bulk ring-opening polymerization of CCL and ?-CL initiated by Sn(Oct)₂. Poly(CCL-co-CL) were characterized by ¹H NMR, ¹³C NMR, SEC and DSC. The copolymer containing 9.1 mol% CCL formed flexible films and was used to study its degradability. A phosphate buffer (pH = 7.4) with temperature 37 °C was adopted to proceed the degrading study all through. Compared with poly(?-caprolactone), the hydrolytic degradation of poly(CCL-co-CL) was much faster, which is confirmed by the weight loss and change of intrinsic viscosity.     

Synthesis and characterization of a novel polytriazole resin with low‐temperature curing character

A novel low‐temperature curing polytriazole resin was prepared from a triazide and a tetraalkyne and characterized. The resin can be cured at 70°C. The glass transition temperature T_g and thermal decomposition temperature T_d5 of the cured resin with the molar ratio of azide to alkyne group [A]/[B] = 1.0:1.0 reached 324 and 355°C, respectively. The study on the curing kinetics of the resin shows that the apparent activation energy of the curing reaction is 93 kJ mol^?1. The flexural strength of the cured resin reached 137.6 MPa at room temperature and 102.6 MPa at 185°C. Copyright © 2007 John Wiley & Sons, Ltd.     

Synthesis and characterization of a novel series of metallothiocarbohydrazone polymers and their adducts

A novel linear polymeric pentadentate (O₂N₂S‐sites) ligand (H₃L) bearing both soft and hard donors was prepared by the reaction of a bifunctional carbonyl compound, 4,6‐diacetylresorcinol, with a bifunctional hydrazide compound, thiocarbohydrazide. Mono‐ and binuclear Cu^II and Ni^II complexes/each monomeric unit of the polymeric ligand were obtained depending on the pH of the reaction medium and the metal ion. Adducts with 1,10‐phenanthroline (Phen) and 2,2′‐bipyridyl (Bpy) were obtained. Anomalous dimeric Co^II/Co^III complexes of the polymeric ligand were obtained in which two molecules of the linear polymeric ligand trapped two cobalt ions (Co^II and Co^III) in each monomeric unit. These structures are very interesting in that they contain Co^II/Co^III, side by side, as high‐spin square planar coordinated Co^II ions and low‐spin (diamagnetic) octahedral coordinated Co^III ions. The suggested structures of the complexes have been elucidated on the basis of elemental and thermal analyses, conductance, and magnetic susceptibility measurements as well as spectral studies (electronic, IR, and ESR spectra). © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:100–107, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20239     

Synthesis and characterization of ureido-containing MQ silicone resin

Abstract

Ureido-containing MQ silicone resin (U-MTQ) was synthesized by the hydrolysis and co-condensation reaction of ethyl silicate, ureido silane, hexamethyldisiloxane, and divinyltetramethyldisiloxane under the catalysis of hydrochloric acid. U-MTQ was characterized by FT-IR, ¹H-NMR, ²⁹Si-NMR, GPC and TGA. The influences of M/Q molar ratio and hydrochloric acid content on the yield and structure of U-MTQ were investigated. The results showed that the M/Q molar ratio of the product calculated from the ²⁹Si-NMR spectrum was much smaller than that in the feed. As M/Q molar ratio in the feed increased, the molecular weight and its distribution index of U-MTQ decreased, and Si-OH content of U-MTQ also decreased, while the structural regularity of U-MTQ was enhanced. With HCl content increasing, the molecular weight and its distribution index of U-MTQ decreased, but the Si–OH content and structural regularity increased. Meanwhile, the yield first increased and then decreased, and reached the highest value of 71.9% when HCl content was 2.10%. Compared with MQ, the onset weight loss temperature of U-MTQ decreased from 237?°C to 158?°C, and the residue at 900?°C increased from 3.5% to 29.5%.