Spectral,thermal, and photoreactivity studies on epoxy resin containing benzylidene units in the main chain

A photosensitive epoxy resin was synthesized from bis(4‐hydroxy ‐3‐methoxy benzylidene) acetone and epichlorohydrin using solution polycondensation method. The prepared epoxy resin was characterized by UV, IR, ¹H NMR, and ¹³C NMR spectroscopy. The thermal stability of the epoxy resin was assessed by thermogravimetric analysis. The glass transition temperature of the polymer was determined by differential scanning calorimetry. The photocrosslinking property and photopolymerizing ability of the epoxy resin were studied in film and solution state using UV spectroscopy. The effect of photo acid generator and sensitizer on photosensitivity of the resin was also investigated. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

光引发阳离子聚合及其在环氧树脂固化研究中的进展

从光引发阳离子聚合的特点、常见阳离子型光敏引发剂及其引发聚合机理、光引发环氧树脂阳离子聚合体系及发展前景等几个方面进行了简要概述。     

Intercalation of epoxy resin in organically modified montmorillonite

Various methods of preparation of epoxy resin/clay mixtures, before the addition of the crosslinking agent and curing to form epoxy‐based polymer layered silicate (PLS) nanocomposites, have been investigated to determine their effect on the nanostructure. Organically modified montmorillonite clay was used, and the mixtures were prepared by both simple mixing and solvent‐based methods. X‐ray diffraction shows that intercalation of the resin into the clay galleries occurs for all clay loadings up to 25 wt % and for both preparation methods, but the dispersion of the clay in the resin, observed by optical microscopy, is significantly better for the solvent preparation method. Differential scanning calorimetry (DSC) shows that the intercalated resin has the same molecular mobility as the extra‐gallery resin, but suggests that the intercalated resin does not penetrate completely into the galleries. Prolonged storage of the resin/clay mixtures at room temperature leads to changes in the DSC response, as well as in the response to thermogravimetry, which are interpreted as resulting from homopolymerization of the epoxy resin, catalyzed by the onium ion in the modified clay. This confirms and explains the earlier observation of Benson Tolle and Anderson (J Appl Polym Sci 2004, 91, 89) that “conditioning” of the resin/clay mixtures at ambient temperature has a significant effect when the crosslinking agent is subsequently added, and indicates that the preparation method has important consequences for the nanostructure development in the PLS nanocomposites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:3751–3763, 2006     

Synthesis, characterization, and properties of novel novolac epoxy resin containing naphthalene moiety

A series of novel novolac epoxy resins containing naphthalene moiety with different molecular weights were synthesized via condensation of bisphenol A and 1-naphthaldehyde, followed by epoxidation with epichlorohydrin. The chemical structure of the naphthalene epoxy thus obtained was characterized using FTIR, ¹H NMR spectra and GPC analyses. The naphthalene epoxy was cured with 4,4′-diaminodiphenyl sulfone (DDS) and the cured products were characterized with thermogravimetric analysis, dynamic mechanical analysis, and X-ray diffraction. Compared with the diglycidyl ether of bisphenol A (DGEBA), the cured naphthalene epoxy resin showed remarkably higher glass transition temperatures (T_gs), enhanced thermal stability and better moisture resistance. When the molar ratio of 1-naphthaldehyde to bisphenol A was 0.67, the optimal thermal resistance was observed.     

新型含磷阻燃环氧树脂的合成与表征

以2-(5,5-二甲基-4-苯基-2-氧代-1,3,2-二氧磷杂环已烷膦酸酯基)-对苯二酚和双酚A 二缩水甘油酯合成了一新型的含环状膦酸酯结构的阻燃环氧树脂(DPODB-EP).采用元素分析、红外光谱(FTIR)和凝胶渗透色谱(GPC)对该含磷环氧树脂的结构和相对分子质量分布进行了表征.采用示差扫描量热法(DSC))和热失重法(TG)对DPODB-EP/PN固化物热性能进行了测试,发现该固化物具有较高的玻璃化转变温度(165℃)和较高的燃烧残炭率(700℃,31%).阻燃性能测试表明该固化物具有较好的阻燃效果,在磷的质量分数为2.25%时其极限氧指数可达29.5%.     

Synthesis of cationic UV‐curable methacrylate copolymers and properties of the cured films of their composites with alicyclic epoxy resin

Cationic UV‐curable methacrylate copolymers consisting of glycidyl methacrylate, iso‐butyl methacrylate, and 2,2,3,4,4,4‐hexafluorobutyl methacrylate were synthesized, and their structures were characterized by FTIR, ¹H NMR, and ¹³C NMR. A series of UV‐cured composite films based on the synthesized copolymers and an alicyclic epoxy resin, 3,4‐epoxycyclohexylmethyl‐3,4‐epoxycyclohexanecarboxylate (CE) were obtained through photopolymerization. Their surface contact angle, chemical ability, gloss, light transmittance, thermal behavior, micromorphology, and shrinkage were investigated. Results indicated that these cured resins showed excellent gloss and visible light transmittance; after the combination of the copolymers and CE, and in the presence of fluorine in the curing systems they exhibited relatively fine water resistance, chemical, and thermal stability. It was observed that these copolymers could decrease the degree of the volume shrinkage to CE. The UV‐curable materials may have promising applications in optical fiber coatings, flip chip and Organic Light‐Emitting Diode (OLED) packing. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis,characterization, thermal,and viscoelastic properties of an unsaturated epoxy polyester cured with different hardeners

The chemical modification of the structure of the unsaturated polyester obtained in poly condensation process of 1,2,3,6‐tetrahydrophthalic anhydride, maleic anhydride, and ethylene glycol by well known conventional method of epoxidation with peracetic acid in mild conditions has been presented. The new material containing both epoxy groups and unsaturated double bonds in polyester chain was characterized by FTIR and ¹H NMR spectra. The prepared unsaturated epoxy polyester was suitable material for further chemical modification. Both epoxy groups and unsaturated double bonds can be used as cross‐linking sites. Curing behavior, thermal, and visco‐elastic properties of the unsaturated epoxy polyester cured with different hardeners: 1,2,3,6‐tetrahydrophthalic anhydride (THPA), hexahydrophthalic anhydride (HHPA), and/or with vinyl monomer (styrene) using radical initiator—benzoyl peroxide (BPO) were studied by differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), and dynamic mechanical analysis (DMA). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of a novel epoxy resin containing pyrene moiety and thermal properties of its cured polymer with phenol novolac

A new epoxy resin containing the pyrene moiety in the backbone (3) was synthesized and confirmed by gel permeation chromatography and field‐desorption mass spectroscopy and infrared spectroscopy. In addition, to evaluate the influence of the pyrene moiety on the structure, epoxy resins having an anthrylene moiety (5) and having a phenylene moiety (7) were synthesized. The cured polymer obtained through the curing reaction between 3 and phenol novolac was used for making a comparison of its thermal properties with those obtained from 5, 7, and bisphenol‐A (4,4′‐isopropylidenediphenyl)‐type epoxy resin (Bis‐EA). The cured polymer obtained from 3 showed a higher glass transition temperature, lower coefficient of linear thermal expansion, lower moisture absorption, and markedly higher anaerobic char yield at 700°C of 37.6 wt %, which might be attributed to the higher aromaticity of 3 containing the pyrene moiety. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 528–535, 2000     

Preparation,characterization, and polymerization of novel maleimidobenzoxazine containing carboxylic moiety and its cocuring behaviors with epoxy resin

A novel benzoxazine containing maleimide and carboxylic moieties, 1‐[3‐(4‐carboxylphenyl)‐3,4‐dihydro‐2H‐benzo[e][1,3]‐oxazin‐6‐yl]maleimide (Mal‐Bz‐Co), was synthesized and the structure was identified by ¹H‐NMR and FTIR. Mal‐Bz‐Co exhibited good solubility in common organic solvents. The cure behavior of Mal‐Bz‐Co and cocure behavior of Mal‐Bz‐Co with o‐cresol formaldehyde epoxy resin were investigated by differential scanning calorimetry. Results indicated that Mal‐Bz‐Co showed a single curing exothermic peak at about 238.3°C. However, the maximum curing temperature (T_p) decreased to 146.1°C when Mal‐Bz‐Co cocured with o‐cresol formaldehyde epoxy resin in the molar ratio of 1 : 1. The T_p was about 92°C lower than that of Mal‐Bz‐Co. Thermogravimetric analysis showed that high‐decomposition temperature and char yield were observed for the cured resins of Mal‐Bz‐Co and Mal‐Bz‐Co/o‐CFER. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

新型含硼苯并噁嗪的合成及其与环氧树脂共混热性能

以乙醇胺、硼酸为原料合成硼酸乙醇胺酯（BAE）,再用所得硼酸乙醇胺酯与多聚甲醛、苯酚反应,合成含硼苯并噁嗪（BAE-BOZ）。将所得BAE-BOZ高温固化,BAE-BOZ和环氧树脂E-51按照不同的质量比进行熔融共混,并经高温固化。采用FT-IR,¹H NMR 和¹³C NMR等分析了BAE-BOZ的化学结构,证明了产物为目标产物;采用DSC对BAE-BOZ的固化特性进行研究;采用TG 分析了含硼乙醇胺型苯并噁嗪poly（BAE-BOZ）和BAE-BOZ/E-51共聚物的热稳定性。结果表明：BAE-BOZ在218℃出现了固化峰;BAE-BOZ的硼含量达到8.67%,在N₂条件下,poly（BAE-BOZ）的热分解温度为302℃,在426℃时热分解速率最快,800℃的残炭率为58.08%,与未经硼改性的乙醇胺型苯并噁嗪（E-BOZ）相比,热分解温度提高40℃,残炭率提高了16.28%;BAE-BOZ/E-51共聚物的热分解温度达到343℃,热性能得到进一步提高。     

Optical properties of bi-doped epoxy novolak resin containing Ce,Dy, and Y ions

In this article, we report on the optical properties of Bismuth doped Epoxy Novolak Resin (ENR) co-doped with Dysprosium, Cerium, and Yttrium ions. The polymer layers containing 1.0 to 20.0 at % of Bismuth were fabricated by spin-coating onto silicon or quartz substrates. The properties of the material were studied using several methods with special regards to its potential utilization in photonics devices. Transmission spectra were taken in the range from 350 to 1600 nm, while photoluminescence spectra around 1300 nm were recorded by using excitation of semiconductor lasers operating at 808 nm and at 980 nm (E_x = 250 mW). Optical properties of the samples were evaluated on the bases of the concentration of the Bismuth ions as well as on the concentrations of the co-doping ions and showed close relations between concentration of the dopants and intensity of the luminescence band at 1300 nm. Our results proved that the Bismuth doped ENR has a strong potential for application in active photonics structures, as it has excellent optical properties and very easy and not demanding fabrication procedures. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Vibrational spectroscopic investigation of light‐induced polymerization process of epoxy resin,polytetrahydrofuran and spirobislactone

The light‐induced polymerization process of bisphenol F diglycidyl ether (BFDGE), 5,5′‐dicarboxylic‐7,7′‐dioxo‐2,2′‐spirodi(benzotetrahydrofuran) (DCSBL) and polytetrahydrofuran (pTHF‐250) was studied. 4‐[(2‐Hydroxytetradecyl)oxy]phenyl‐phenyliodoniumhexafluoroantimonate, camphorquinone and ethyl 4‐dimethylaminobenzoate were used as a photoinitiator system. The polymerization process was induced by light and monitored using Fourier transform infrared spectroscopy. A novel combination‐initiation polymerization process was proposed: first, cationic copolymerization of BFDGE and pTHF‐250 was initiated by the photoinitiator system and heat was released by this polymerization; then, copolymerization of BFDGE and DCSBL was induced by that heat while pTHF‐250 served as an anionic initiator. Copyright © 2007 Society of Chemical Industry     

Synthesis,characterization, and properties of a novel epoxy resin containing both binaphthyl and biphenyl moieties

A new epoxy resin containing both binaphthyl and biphenyl moieties in the skeleton (BLBPE) was synthesized and confirmed by electrospray ionization mass spectroscopy, ¹H‐nuclear magnetic resonance spectroscopy, and infrared spectroscopy. To evaluate the combined influence of two moieties, one epoxy resin containing binaphthyl moiety and another containing biphenyl moiety were also synthesized, and a commercial biphenyl‐type epoxy resin (CER3000L) was introduced. Thermal properties of their cured polymers with phenol p‐xylene resins were characterized by differential scanning calorimetry, dynamic mechanical, and thermogravimetric analyses. The cured polymer obtained from BLBPE showed remarkably higher glass transition temperature and lower moisture absorption, as well as comprehensively excellent thermal stability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Curing behavior and thermal property of epoxy resin with boron‐containing phenol‐formaldehyde resin

The curing reaction of bisphenol‐A epoxy resin (BPAER) with boron‐containing phenol–formaldehyde resin (BPFR) was studied by isothermal and dynamic differential scanning calorimetry (DSC). The kinetic reaction mechanism in the isothermal reaction of BPAER‐BPFR was shown to follow autocatalytic kinetics. The activation energy in the dynamic cure reaction was derived. The influence of the composition of BPAER and BPFR on the reaction was evaluated. In addition, the glass transition temperatures (T_gs) were measured for the BPAER‐BPFR samples cured partially at isothermal temperatures. With the curing conditions varying, different glass transition behaviors were observed. By monitoring the variation in these T_gs, the curing process and the thermal property of BPAER–BPFR are clearly illustrated. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1054–1061, 2000     

Toughened cycloaliphatic epoxy resin for demanding thermal applications and surface coatings

An epoxy resin based on nonglycidyl ether and varying content of carboxyl‐terminated (poly)butadiene acrylonitrile copolymer was cured using an aromatic amine hardener. The ultimate aim of the study was to modify the brittle epoxy matrix by the liquid rubber to improve toughness characteristics. Fourier transform infrared spectroscopic analysis of the modified was performed to understand the structural transformations taking place during the uncured and cured stage of the modified systems. The decreasing trend in exothermal heat of reaction with increasing rubber content in the epoxy resin can be explained by the fact that the increase of carboxyl‐terminated butadiene acrylonitrile copolymer (CTBN) modifier might induce a high reactivity of the end groups with the epoxide ring and resulting shorter curing times and, hence, the faster curing process than the unmodified resin. Tensile strength, impact strength, and elongation‐at‐break behaviors of neat as well as modified networks have been studied to observe the effect of rubber modification. Blends sample exhibits better properties as compared to pure epoxy resin in terms of increase in impact strength and elongation‐at‐break of the casting and gloss, scratch hardness, adhesion, and flexibility of the film. The improvement in these properties indicate that the rubber‐modified resin would be more durable than the epoxy based on di glycidyl ether of bis‐phenol‐A and other epoxies. The films of coating based on epoxy with 15 wt % CTBN offered the maximum resistance toward different concentrations of acids, alkalies, and solvents as compared to the cured films of other blend samples. The thermal stability of the cycloaliphatic‐based epoxy resin was increased with the addition of 15 wt % CTBN in epoxy matrix. Cycloaliphatic‐based epoxy network modified with CTBN displayed two phase separated morphology with dispersed rubber globules in the matrix resin, i.e., they revealed the presence of two phase morphological features. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Side‐chain liquid‐crystalline polymers with a limonene‐co‐methyl methacrylate main chain: Synthesis and characterization of polymers with phenyl benzoate mesogenic groups

A new series of liquid‐crystalline polymers with a polymer backbone of limonene‐co‐methyl methacrylate were synthesized and characterized, and the spacer length was taken to be nine methylene units. The chemical structures of the obtained olefinic compound and polymers were confirmed with elemental analysis and proton nuclear magnetic resonance spectroscopy. The thermal behavior and liquid crystallinity of the polymers were characterized with differential scanning calorimetry and polarized optical microscopy. The polymers exhibited thermotropic liquid‐crystalline behavior and displayed a glass‐transition temperature at 48°C. The appearance of the characteristic schlieren texture confirmed the presence of a nematic phase, which was observed under polarized optical microscopy. These liquid‐crystalline polymers exhibited optical activity. A comparison was also made with polyacrylates and polymethacrylate‐based materials. This revealed that the nature of the polymer backbone had a major effect on the liquid‐crystalline properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4595–4600, 2006     

Thermally initiated cationic polymerization and properties of epoxy siloxane

Difunctional epoxy siloxane monomers containing disiloxane, trisiloxane, and tetrasiloxane were prepared by hydrosilylation of an α,ω‐difunctional Si? H‐terminated siloxane with a vinyl‐functional epoxide. Cationic polymerization of these monomers using 3‐methyl‐2‐butenyltetramethylenesulfonium hexafluoroantimonate and their reactivities were examined. The reactivity order was disiloxane > trisiloxane > tetrasiloxane. Thermal discoloration of these polymers increased with catalyst concentration and also with the length of dimethyl siloxane. UV discoloration was also accelerated by catalyst. From the thermo gravimetric analysis, it was found that the thermal stabilities of polymers increased with increasing the length of dimethyl siloxane chain. Mechanical properties of polymers were also tested by thermal mechanical analysis and dynamic mechanical analysis, and it was found that the flexibility of polymers was increased with increasing siloxane chain length. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2010–2019, 2006     

Synthesis and application of a novel epoxy grafted thermosetting acrylic resin

A novel manufacturing process for high performance metallic can coating was carried out based on an epoxy‐grafted acrylic resin. Firstly, the epoxy resin was reacted with acrylic amide forming a ring opened product epoxy‐amide resin, and then the product obtained copolymerized with all other monomers, such as acrylic acid (AA), butyl acrylate (BA), hydroxypropyl acrylate (HPA), 2‐ethylhexyl acrylate (2‐EHA), methyl methacrylate (MMA), styrene (St), using free radical solvent polymerization in the presence of BPO. The resins prepared present the transparent appearance, and the target resin coating based on these resins exhibits excellent boiling resistance and chemicals resistance and can be applied as the protective coating for metallic can. The effects on the coating properties, such as amount of acrylic acid, 2‐EHA wt % between 2‐EHA and BA, amount of amino resin, amount of catalyst, and so forth, were investigated. In addition, the influences of polymerization time on the conversion ratio of monomers were also studied. Results show that under the optimal conditions, the target resin coating provides excellent physical and mechanical properties. The various properties tests for this coating have been performed in accordance with the standards of ASTM. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of Alkyl‐Functionalized Hyperbranched Polymers and Their Use as Additives in Cationic Photopolymerization of Epoxy Resins

Summary: An alkyl‐functionalized hyperbranched polymer, HBP(OH)–C16, was synthesized by partial modification with fatty acid of an aromatic‐aliphatic OH‐terminated hyperbranched polyester HBP? OH. This product was used as additive in the cationic photopolymerization of an epoxy resin. The alkyl‐modified polyester takes part in the photopolymerization process thanks to the residual OH groups by means of chain‐transfer reactions. An increase of the epoxy conversion is observed by increasing the amount of the HBP additive in the photocurable resin with a modification of the bulk properties of the final ultraviolet‐cured films. The presence of HBP(OH)–C16 induces an increase in glass transition temperature, thermal stability, and solvent resistance. Moreover the surface properties of the films are modified achieving highly hydrophobic surfaces in the presence of even very low amounts of HBP(OH)–C16.

Structure of HBP–C16.