Tetrakis(4-(1-bromoethyl)phenyl)silane is synthesized and utilized to initiate the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) to generate bromo-terminated four-armed PMMA macroinitiators, which further initiate the ATRP of methylacryloyloxyl-2-hydroxypropyl perfluorooctanoate (FGOA) to create fluorinated star-shaped block copolymers PMMA-b-poly(FGOA)s with fluorine content ranging from 0 to 31.7 wt %. The polymerizations are well controlled with the polydispersity indices <1.30. The polymers readily dissolve in common organic solvents and show good film-formation. Compared with the nonfluorinated sample, the fluorinated films exhibit significantly increased water contact angles owing to the enrichment of fluorine on the surface. The enhanced hydrophobicity is advantageous for the optical stability when the devices work under a moist environment. Moreover, the films possess high thermo-optic coefficients, tunable refractive indices, and extremely low birefringence coefficients because of the presence of bulky and rigid tetraphenylsilane core and star-shaped topological structure, showing potential application in optical waveguide devices. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1969–1977

The aim of this paper is to systematically investigate the curing behavior of three novel di- and trifunctional silicon-containing cycloaliphatic epoxy resins by both anhydride and cationic ring-opening polymerization methods as well as the viscoelasticity, thermal stability, water absorption and optical properties of the cured products. Differential scanning calorimetry curves show that, relative to anhydride curing, cationic polymerization can decrease the curing temperature to below 120 °C, and the reaction exothermic peaks become very narrow and sharp, exhibiting rapid curing characteristics at moderately low temperature. In addition, the differences between the anhydride and cationic curing methods bring about interesting variations in physical properties for the cured products which are well related to their chemical structures, polymerization mechanism, crosslinking density, segmental flexibility and inter-segmental distance. The excellent transparency, rapid cationic curing rate, good thermal stability and high glass transition temperature of over 275 °C make this series of epoxy resins promising candidates for light-emitting diode encapsulation applications. © 2012 Society of Chemical Industry

Hyper-cross-linked polycyanurate networks (CE-P1 and CE-P2) were synthesized by means of thermal self-cyclotrimerization from two triangular cyanate resin monomers 1,3,5-tri(4-cyanatophenyl)benzene and 1,3,5-tricyanatobenzene, respectively. Interestingly, it was found that CE-P1 exhibited microporous characteristics and a moderately large BET surface area. The two narrow peaks in the nonlocal density functional theory (NLDFT) curve appeared at 0.57 and 1.01 nm. In contrast, the CE-P2 sample had a small surface area and broad pore-size distribution with major pores of around 3.39 nm, which indicated a mesoporous material. The reason for this was interpreted in terms of the geometric configuration, steric hindrance, and reactivity of the cyanate monomers. The adsorptions of CO₂, H₂, benzene, n-hexane, and water vapors were investigated by correlating the data with the porosity parameters, chemical structure, and composition of the two networks. The results showed that the vastly distinct pore properties significantly influenced the adsorptions of gases and vapors. In particular, organic vapors such as benzene and n-hexane tended to be adsorbed on the pore surface owing to their affinity and thereby the adsorption amounts were tightly attached to the surface area of the samples. On the contrary, the hydrophobic nature of polymers made the water molecules preferentially condense within the pores so that the pore size rather than the surface area became the dominant factor influencing the adsorption of water vapor.

In this paper, two silicon-containing cycloaliphatic olefins were synthesized through the nucleophilic substitution reactions of cyclohex-3-enyl-1-methanol with di- or tri-chlorosilane compounds. Then, after epoxidation, two new cycloaliphatic epoxy resins with different epoxy groups were successfully prepared. Their chemical structures were confirmed by ²⁹Si NMR, ¹H NMR, and Fourier-transform infrared spectra (FTIR). The properties of cured products, including viscoelasticity, glass transition temperature (T_g), coefficient of thermal expansion, thermal stability and water absorption, were investigated. Compared to the difunctional epoxy resin, the trifunctional one exhibited a remarkably increased cross-linking density from 0.82 to 4.08 × 10⁻³ mol/cm³ and T_g from 157 to 228°C. More importantly, prior to curing, they had viscosities of only 240–290 mPa sec at 25°C, which were much lower than that of ERL-4221 (409 mPa sec), providing the possibility of easy processing. The high glass transition temperatures, good thermal stabilities, and mechanical properties as well as excellent flowability endow the silicon-containing epoxy resins with promising potential in microelectronic packaging application. Copyright © 2011 John Wiley & Sons, Ltd.

A series of novel dysprosium coordination polymers were synthesized using new high-T_g carboxyl-containing polyaryletherketones (PEKs) as macromolecular ligands and a small molecule, 1,10-phenanthroline, as co-ligand. The FTIR, WAXD, and UV–Vis results indicated that the dysprosium ions were coordinated simultaneously with carboxyl group of PEKs and 1,10-phenanthroline, and homogeneously distributed along the polymer backbone. These obtained dysprosium coordination polymers showed excellent film-formation properties. Moreover, all the dysprosium coordination polymers could exhibit the intense characteristic emission of dysprosium ions under UV excitation. Meanwhile, the emission intensity increased with increasing dysprosium ion content, and no obvious fluorescence quenching happened at the Dy³⁺ ion content up to 10.71 wt%, which was attributed to the very rigid structure of PEK and synergistic coordination effect of PEK and 1,10-phenanthroline. Copyright © 2009 John Wiley & Sons, Ltd.

1,10-Phenanthroline-functionalized polyaryletherketone (PPEK) was synthesized by the amidation reaction of 5-amino-1,10-phenanthroline with polyaryletherketone containing pendant acyl chloride groups. Subsequently, a series of novel rare earth coordination polymers (with rare earths Eu³⁺, Tb³⁺, Sm³⁺ and Dy³⁺) were prepared, using PPEK as macromolecular ligand and the small 1,10-phenanthroline (Phen) molecule as synergistic ligand. Their structures were characterized using Fourier transform infrared spectroscopy, elemental analysis and X-ray diffraction, which confirmed that both PPEK and Phen participated in the coordination reaction with the rare earth ions, and that the rare earth ions could disperse homogeneously in the polymer matrix. The rare earth coordination polymers were soluble in polar solvents such as N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone, and could be easily cast into transparent tough thin films. Fluorescence measurements indicated that all the coordination polymers exhibited the intense characteristic fluorescence of the corresponding rare earth ions under ultraviolet excitation, showing their application potential in optical display devices. Copyright © 2010 Society of Chemical Industry

This article presents a new type of epoxy-toughening system, in which high-T_g polyaryletherketone (PEK-L) containing one carboxyl group per repeating unit was utilized to randomly copolymerize with epoxy resin (DGEBA) to form crosslinking network. Compared to the neat epoxy resin, the PEK-L/DGEBA copolymers showed simultaneous enhancement in flexural strains at break by 282%, G_IC value by 193%, and flexural strength by 14%. The reason was attributed to the uniform three-dimensional copolymer network interweaved by PEK-L and DGEBA segments through strong covalent bonds. The copolymerization process were monitored and examined by FTIR spectra. The effect of copolymer composition on the thermal and mechanical properties as well as toughening mechanism were also investigated and discussed in detail. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010

BACKGROUND: An ester-free cycloaliphatic di-epoxide, bis(2,3-epoxycyclohexyl), with epoxycyclohexyl moieties linked via carbon–carbon bonds was synthesized and characterized. The photopolymerization of the di-epoxide was systemically investigated in the presence of different diols, 1,2-ethanediol, 1,4-butanediol, 1,2-propanediol and pinacol, using real-time Fourier transform infrared spectroscopy to follow the reaction process.

RESULTS: Among the four diols, the presence of pinacol resulted in the fastest photopolymerization rate and highest degree of conversion of di-epoxy groups, but a relatively low gel content, while the addition of 1,2-ethanediol led to an inhibiting effect on the di-epoxide reaction rate, but the product showed the highest gel content. The influences of the diols on the cationic photopolymerization behavior of the di-epoxide were explained according to the steric hindrance, proton-trapping ability and electronic effect of the diols.

CONCLUSION: The study results provide the possibility to conveniently manipulate the photopolymerization rate and modify the properties of an epoxy resin by simply adjusting the structure and amount of added diol in the polymerization system to meet the demands for potential microelectronic and optoelectronic packaging applications. Copyright © 2008 Society of Chemical Industry

BACKGROUND: Reactive thermoplastics have received increasing attention in the field of epoxy resin toughening. This paper presents the first report of using a novel polyaryletherketone bearing one pendant carboxyl group per repeat unit to cure the diglycidyl ether of bisphenol-A epoxy resin (DGEBA). The curing reactions of DGEBA/PEK-L mixtures of various molar ratios and with different catalysts were investigated by means of dynamic differential scanning calorimetry and Fourier transform infrared (FTIR) spectroscopy methods.

RESULTS: FTIR results for the DGEBA/PEK-L system before curing and after curing at 135 °C for different times demonstrated that the carboxyl groups of PEK-L were indeed involved in the curing reaction to form a crosslinked network, as evidenced by the marked decreased peak intensities of the carboxyl group at 1705 cm⁻¹ and the epoxy group at 915 cm⁻¹ as well as the newly emerged strong absorptions of ester bonds at 1721 cm⁻¹ and hydroxyl groups at 3447 cm⁻¹. Curing kinetic analysis showed that the value of the activation energy (E_a) was the highest at the beginning of curing, followed by a decrease with increasing conversion (α), which was attributed to the autocatalytic effect of hydroxyls generated in the curing reaction.

CONCLUSION: The pendant carboxyl groups in PEK-L can react with epoxy groups of DGEBA during thermal curing, and covalently participate in the crosslinking network. PEK-L is thus expected to significantly improve the fracture toughness of DGEBA epoxy resin. Copyright © 2009 Society of Chemical Industry