Cardo poly (ether sulfone) toughened E51/DETDA epoxy resin and its carbon fiber composites

A toughener that can effectively improve the interlaminar toughness in carbon fiber composites is crucial for various applications.We investigated,the toughening effects of phenolphthalein-based cardo poly(ether sulfone)(PES-C)on E51/DETDA epoxy and its carbon fiber composites(CFCs).Scanning electron microscopy showed that the phase structures of PES-C/epoxy blends change from island(of dispersed phase)structures to bi-continuous structures(of the matrix)as the PES-C content increased,which is associated with reaction-induced phase separation.After adding 15 phr PES-C,the glass transition temperature(T_(g))of the blends increased by 51.5℃,and the flexural strength,impact strength and fracture toughness of the blends were improved by 41.1%,186.2%and 42.7%,respectively.These improvements could be attributed to the phase separation structure of the PES-C/epoxy sys-tem.A PES-C film was used to improve the mode-II fracture toughness(G_(IIC))of CFCs.The G_(IIC) value of the 7μm PES-C film toughened laminate was improved by 80.3%compared to that of the control laminate.The increase in G_(IIC) was attributed to cohesive failure and plastic deformation in the interleaving region.

STUDY ON HYDROLYSIS RESISTANT POLYCARBONATE POLYURETHANE EPOXY RESIN BLENDS

This paper studies the structure and properties of the polycarbonate polyurethane epoxy resin (PCPU EP) blends being resistant to hydrolysis.The samples were analyzed by an infrared spectrometer,a differential scanning calorimeter,a scanning electron microscope and a dynamic viscoelastometer.The results show that PCPU EP blends have excellent resistance to hydrolysis and mechanical properties at the ratio of PCPU to EP equal to 10/100 (wt/wt).

Optimization of reaction for synthesis of polyisobutylene amine between amination agent and epoxy polyisobutylene

An optimization study on the amination reaction of epoxy polyisobutylene for synthesis of polyisobutylene amine is presented. The experimental results indicate that n-butanol and ethylenediamine are the suitable solvent and amination agents for the reaction, respectively. The reaction yield of the amination reaction is notably increased with the enhanced molar ratio of either n-butanol against epoxy polyisobutylene or ethylenediamine against epoxy polyisobutylene. Also, the yield is enhanced with increasing temperature and time during the experimental range. Strikingly, the yield reaches as high as 91. 30% under optimal conditions; with the molar ratio of ethylenediamine, n-butanol and PIBO of 10∶ 6∶ 1, the reaction temperature of 150 ℃ and the reaction time of 6 h. In addition, the yield of the reaction is slightly decreased with the enhanced water content of the system. Accordingly, the mass concentration of water should be controlled within 1. 7% during the reaction.

Polybutylacrylate/poly(methyl methacrylate) Core-Shell Elastic Particles as Epoxy Resin Toughener: Part I Design and Preparation

Polybutylacrylate (PBA)/poly(methyl methacrylate) (PMMA) core-shell elastic particles (CSEP), whose rubbery core diameter ranged from 0.08 μm to 1.38μm, were synthesized by using conventional emulsion polymerization, multi-step emulsion polymerization, and soapless polymerization. Allyl methacylate (ALMA) and ethylene glycol dimethacrylate (EGDMA) were selected as crosslinking reagents for core polymerization. Methacrylic acid (MAA) was used as functional co-monomer with methyl methacrylate as shell component. The content of vinyl groups in PBA rubbery core increased with the amount of crosslinking reagents. The core-shell ratio affected great on the morphology of the complex particles. Furthermore, the amounts of carboxyl on the surface of core-shell particles, copolymerized with acrylic acid, were determined by potentiometric titration. Results showed that methylacrylic acid was distributed mostly on the surface of particles.

Improvements of heat resistance and adhesive property of condensed poly-nuclear aromatic resin via epoxy resin modification

A bisphenol epoxy resin was used as modifier to increase the heat resistance of condensed poly-nuclear aromatic （COPNA） resin. The basic properties of COPNA resin and modified resin were characterized by Fourier transform infrared spectroscopy （FT-IR）, nuclear magnetic resonance spectroscopy （1H-NMR）, vapor pressure osmometry （VPO） and elemental analysis （EA）. Average structural parameters of resins were calculated by the improved Brown-Ladner method, and heat resistance of resins was tested by thermogravimetric analysis （TGA）. The chemical structure, mechanical properties and heat resistivity of the resin/graphite composites prepared with different resins were compared. The results show that the adhesive property and heat resistance of COPNA resin can be remarkably improved by addition of 5 wt.% epoxy resin. The reason is that the reactions between epoxy groups of epoxy resin and hydroxyl groups of COPNA resin improve the heat resistance and adhesive property of COPNA resin. Electric motor brushes with good mechanical properties and low electrical resistivity were successfully prepared by using the modified resin as binder.

Toughening of Epoxy Resin with Solid Amine Terminated Poly(ethy-lene glycol) Benzoate and Effect of Red Mud Waste Particles

An investigation was carried out to modify the toughness of triethylene tetramine cured DGEBA （diglycidyl ether of bisphenol-A） resin using solid amine terminated poly （ethylene glycol） benzoate （ATPEGB） as modifier with and without red mud waste particles. The solid ATPEGB modifier synthesized from the acid catalyzed esterification reaction of poly （ethylene glycol） （PEG） and 4-amino benzoic acid was characterized by Fourier transform infrared spectroscopy （FT-IR） and ^1H-NMR （nuclear magnetic resonance） spectroscopies, viscosity measurements, and solubility parameter calculation. The unfilled and red mud waste filled modified epoxy networks were evaluated with impact, adhesive, tensile, flexural and thermal properties by differential scanning calorimetry （DSC）, thermogravimetric （TG） and dynamic mechanical analysis （DMA）. The effect of modifier concentration and red mud waste particles on toughening behavior was also investigated. The optimum properties were obtained at 12.5 phr （parts per hundred parts of resin） concentration of the modifier. The ATPEGB modified cured epoxy was thermally stable up to 315℃. The morphology on fracture surfaces of cured epoxy was also analyzed by scanning electron microscopy （SEM）.

Preparation and Characterization of Carboxyl-terminated Poly(butadiene-co-acrylonitrile)-epoxy Resin Prepolymers for Fusion-bonded-epoxy Powder Coating

Liquid carboxyl-terminated poly（butadiene-co-acrylonitrile）（CTBN）-epoxy resin（EP） prepolymers were prepared with different contents of CTBN.The chemical reactions between EP and CTBN were characterized by Fourier ransform infrared（FTIR） spectroscopy and gel permeation chromatography（GPC）.The scanning electron micrograph（SEM） and dynamic mechanical analysis（DMA） of curing films showed phase separation,and the rubber particles were finely dispersed in the epoxy matrix.Mechanical properties analysis of curing films showed that impact strength and elongation at break increased significantly upon the addition of CTBN,indicating good toughness of the modified epoxy resins.Thermogravimetric analysis（TGA） showed that the incorporation of CTBN had little effect on the thermal stability of EP.Fusion-bonded-epoxy（FBE） powder coatings modified with CTBN-EP prepolymers were prepared.The experimental results demonstrate the ability of CTBN-EP prepolymers,toughening technology to dramatically enhance the flexibility and impact resistance of FBE coatings without compromising other key properties such as corrosion protection.

Synthesis of Composite Nanoparticles Bearing Epoxy Functional Groups:Encapsulation of Silica by Emulsion Polymerization of GMA

Poly （ glycidyl methacrylate ） / silica （PGMA/silica） composite nanoparticles , containing epoxy functional groups on the surface, were synthesized via emulsion polymerization. With batch process, high yield and binding efficiency （ both around 90% ） were achieved. The amount of crosslinked GMA was approximately 8wt%- 14wt% to the polymerized monomer. It was found that both the encapsulating ratio and the number of the original silica beads per composite particles altered with the amount of silica added. The obtained particles, with their average particle size of about 60- 70 nm, had a spherical shape and a clear core- shell structure.

Polybutylacrylate/poly (methyl methacrylate) Core-Shell Elastic Particles as Epoxy Resin Toughener: Part Ⅱ Toughness on DGEBA/DDM system

Mechanlcal properties of epoxy resin were investigated by adding core-shell elastic particles (CSEP). The results indicated that optimized core-shell ratio was 60/40 and the loading volume of CSEP was 10 phr (per hundred parts of epoxy resin by weight). The impact strength of modified systems increased apparently with the decrease of core sizes. However, the shearing strength changed gently with the particle sizes. CSEP with lightly crosslinked rubbery core showed more effectiveness on toughness than others. With solution blending, CSEP could be dispersed in epoxy matrix well, and the morphologies of dispersed rubber domains were controlled perfectly by CSEP whose structure was predesigned. A cavitation-shearing band toughness mechanism was observed from the SEM micrographs of fracture surface. It also was found that the deforming temperature (DT) of modified epoxy did not decline apparently.

Melt Synthesis and Characterization of Poly(L-lactic Acid) Chain Linked by Multifunctional Epoxy Compound

High molecular weight（Mw） poly（L-lactic acid）s（PLLAs） were synthesized using multifunctional epoxy compound（Joncryl-ADR4370） as chain extender. The products were characterized by gel permeation chromatography（GPC） and spectroscopy（1HNMR and FTIR）. The results indicated that the Mw of PLLA increased with the increasing of the ratio of epoxy compound and the extending of reaction time. The highest Mw of PLLA reached 360 000 g/mol when the ratio of epoxy compound was 1.5 wt%. However, the reactants turned to cross-linking when the ratio of epoxy compound was over 1.5 wt%. Differential scanning calorimetry（DSC） measurements demonstrated that the glass transition（Tg） and melting temperatures（Tm） of products increased slightly as the increase of the molecular weight. Analysis of the hydrolytic degradation in vitro showed that the branched PLLA possessed the quicker degradability than that of the linear PLLA.

Immobilization of penicillin G acylase on paramagnetic polymer microspheres with epoxy groups

Paramagnetic polymer microspheres were synthesized by the inverse suspension polymerizationmethod through polymerization of glycidyl methacrylate,ally glycidyl ether and methacrylamide onthe surface of silica‐coated Fe3O4nanoparticles using N,N’‐methylene‐bis(acrylamide)as across‐linking agent.Penicillin G acylase(PGA)was covalently immobilized on the surface of theparamagnetic microspheres by reacting the amino groups of the PGA molecules with the epoxygroups of the paramagnetic polymer microspheres.The effect of the SiO2coating and the amount ofparamagnetic Fe3O4nanoparticles on the initial activity and the operational stability of the immobilizedPGA was investigated.The results indicated that SiO2played an important role in the polymerization process and paramagnetic polymer microspheres with a SiO2‐coated Fe3O4nanoparticles mass content of7.5%are an optimal support material for PGA immobilization.Immobilized PGA on the paramagnetic polymer microspheres shows a high initial activity of430U/g(wet)and retains99%of its initial activity after recycling10times.Furthermore,immobilized PGA exhibits high thermal stability,pH stability and excellent reusability,which can be rapidly recycled by the aid of magnet.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.

Effect of Hyperbranched Polyester on Modification of Epoxy Resins Cured with Anhydride

The synthesis and characterization of hyperbranched polyester （HBP） with different molecular weight are studied. The effect of HBP on the modification of epoxy resins cured with anhydride is mainly discussed. The characteristics of HBP and the morphologies of cured system are determined by nuclear magnetic resonance spectroscopy （NMR）, gel permeation chromatography （GPC） and scanning electron microscope （SEM）. The impact strength of cured system is detected and Fourier transform infrared （FTIR） measurements were used to pursue the curing process. The investigation shows that HBP can improve the toughness by forming copolymer networks between epoxy resins, HBP and anhydride. Moreover, when the molecular weight of HBP is 1342g/mol the toughening effect is the best, and the changes of toughness are small with the increase of molecular weight of HBP to 3500 g/mol.

MODIFICATION OF EPOXY RESINS WITH PHENOLIC HYDROXYL-TERMINATED POLYSILOXANE

Phenolic hydroxyl-terminated polysiloxanes were incorporated into epoxy resins to reduce the internal stress owing to the mismatch in coefficient of thermal expansion (CTE). Polysiloxane-epoxy resin block copolymers were made by a pre-reaction step prior to the curing. In the cured resin, the domain size of the polysiloxane phase depended on the structure of the phenolic hydroxyl-terminated polysiloxane. It was found that the modulus of the cured resin depended largely on the level of the modifier, while the CTE was affected greatly by the structure of the polysiloxane. By means of incorporating a few percent of methylphenylsiloxane unit into the polydimethylsiloxane chain, or by introducing; more compatible end-capping groups, the compounds of more effective low stress modifiers were synthesized.

STUDIES ON THE INTERACTION OF EPOXY POLYMERS WITH HOMOPOLYUREAS

INTRODUCTION Epoxy resins are reactive polymers which when cured with a variety of chemicals lead to a host of useful thermosets. Since the epoxide is a strained ring, it readily undergoes addition and homopolymerization. The homopolymerization is a process catalysed by acids, bases, Lewis acids, t-amines as well as by inorganic salts.

Preparation and Characterization of Non-porous Superparamagnetic Microspheres with Epoxy Groups by Dispersion Polymerization

Non-porous superparamagnetic polymer microspheres with epoxy groups were prepared by dispersion polymerization of glycidyl methacrylate (GMA) in the presence of magnetic iron oxide (Fe3O4) nanoparticles coated with oleic acid. The polymerization was carried out in the ethanol/water medium using polyvinylpyrrolidone (PVP) and 2,2’-azobisisobutyronitrile (AIBN) as stabilizer and initiator, respectively. The magnetic microspheres obtained were characterized with scanning electron microscopy (SEM), vibrating sample magnetometry (VSM) and Fourier transform infrared spectroscopy (FTIR). The results showed that the magnetic microspheres had an average size of-1μm with superparamagnetic characteristics. The saturation magnetization was found to be 4.5emu.g-1. There was abundance of epoxy groups with density of 0.028 mmol·g^-1 in microspheres. The magnetic PGMA microspheres have extensive potential uses in magnetic bioseparation and biotechnology.

Synthesis and Characterization of Novel Sulphanilamide/Epoxy Resin Modified Polyester for Thermal Stability and Impact Strength

The synthesis of thermally stable Tetra-di-glycidyl ether bisphenol-A (TDGEBA) Epoxy resin and Sulphanilamide (SAA) have been synthesized from (SAA) and TDGEBA by in situ polymerization technique to obtain Te-tra-di-glycidyl ether bisphenol-A Sulphanilamide (TDGEBA/SAA) Epoxy resin and modified with various per-centages of polyester (PE) to obtain Tetra diglycidyl ether bisphenol-A Sulphanilamide polyester (TDGEBA/SAA-PE), highly cross-linked thermosetting polymer network. These materials were cured with triethylenetetramine TETA (hardener) to obtain highly cross-linked thermosetting resin. The physical properties of the resulting blends were evaluated by measuring the impact strength of (TDGEBA/SAA-PE) (increased more than 30% than the unmodified epoxy resin) and hardness that is found to be higher than unmodified epoxy resin. Differential scanning calorimetry (DSC) and thermo gravimetric (TGA) analysis were also cured to assess the thermal behavior of the samples. DSC of the (TDGEBA/SAA) Epoxy resin cured with TETA showed exothermic reactions and the glass transition temperature (Tg) shifted from 350℃ to 400℃compared with uncured epoxy and the thermal stability of the TDGEBA/SAA epoxy resin modified increased with increasing of PE. Scanning Electron Microscopy (SEM) studied the morphology of the samples after unnotched impacts on fracture surfaces. These materials exhibited a higher degree of solvent resistance.

Effect of Epoxy Resin on Mechanical Properties of Metakaolin based Geopolymer and Microscopic Analysis

By using NaOH and Na2SiO3 as the activator,the mechanical properties and shrinkage of the geopolymer after incorporation of 0%,10%,20%,and 30% epoxy resin were investigated.The mechanism of epoxy resin toughening metakaolin based geopolymer was analyzed by X-ray diffraction,scanning electron microscopy and Fourier transform infrared spectroscopy.It was shown that with the increases of epoxy resin,the shrinkage performance was obviously improved and the flexural strength increased by 53.5%.The compressive strength of EGP10,EGP20,and EGP30 increased by 49.12%,57.04%,and 65.34% after curing for 28 days,respectively.There were five obvious vibration peaks of 811 cm^-1,1 000 cm^-1,1 050 cm^-1,1 590cm^-1,and 3 400 cm^-1 in the geopolymer and the undisturbed metakaolin.More geopolymer gels were formed in the material and the microstructure was more compact.

Developing polydopamine modified molybdenum disulfide/epoxy resin powder coatings with enhanced anticorrosion performance and wear resistance on magnesium lithium alloys

Epoxy resin powder coating has been successfully applied on the corrosion protection of magnesium lithium alloys.However,poor wear resistance and microcracks formed during the solidification have limited it extensive application.There are limited approaches to exploit such anti-corrosion and mechanical properties of magnesium lithium alloys.Herein,the epoxy resin powder coating with polydopamine modified molybdenum disulfide(MoS_(2)@PDA-EP powder coating with 0,0.1,0.2,0.5,1.0 wt.%loading)was well prepared by melt extrusion to investigate its anticorrosion performance and wear resistance.The results revealed that the addition of MoS_(2)@PDA enhanced the adhesion strength between coatings and alloys,wear resistance and corrosion protection of the powder coatings.Among them,the optimum was obtained by 0.2 wt.%MoS_(2)@PDA-EP powder coating which could be attributed to well dispersion and efficient adhesion with coating matrix.To conclude,MoS_(2)@PDA-EP powder coating is meaningfully beneficial for the anticorrosive and wear performance improvement of magnesium lithium alloys.

Curing mechanism of TDE-85/MeTHPA epoxy resin modified by polyurethane

Diglycidyl 4,5-epoxy tetrahydro phthalate/methyl tetrahydrophthalic anhydride （TDE-85/MeTHPA） epoxy resin modified by polyurethane （PU） was prepared with 1,4-butanediol （1,4-BDO）, trimethylol propane （TMP） and polyurethane prepolymer synthesized by polypropylene glycol and toluene diisocynate. Chemical reaction and curing mechanism of this system were discussed by incorporating the results of infra spectrum analysis. The results indicate that the epoxy polymeric network I is obtained by the curing reaction between TDE-85 and MeTHPA, while the PU polymeric network II is obtained by the chain-extended and crosslinking reaction between 1,4-BDO, TMP and polyurethane prepolymer（PUP）. The graft chemical bonds are formed between polymer networks I and II that therefore increase the degree of blend and compatibility between epoxy polymer and PU.

Structural characteristics and properties of polyurethane modified TDE-85/MeTHPA epoxy resin with interpenetrating polymer networks

Diglycidyl-4,5-epoxycyclohexane-1,2-dicarboxylate(TDE-85)/methyl tetrahydrophthalic anhydride (MeTHPA) epoxy resin was modified with polyurethane(PU) and the interpenetrating polymer networks(IPNs) of PU-modified TDE-85/MeTHPA resin were prepared. The structural characteristics and properties of PU-modified TDE-85/MeTHPA resin were investigated by Fourier transform infrared(FTIR) spectrum,emission scanning electron microscopy(SEM) and thermogravimetry(TG). The results indicate that epoxy polymer network (Ⅰ) and polyurethane polymer network (Ⅱ) of the modified resin can be obtained and the networks (Ⅰ) and (Ⅱ) interpenetrate and tangle highly each other at the phase interface. The micro morphology presents heterogeneous structure. The integrative properties of PU-modified TDE-85/MeTHPA epoxy resin are improved obviously. The PU-modified TDE-85/ MeTHPA resin's tensile strength reaches 69.39 MPa,the impact strength reaches 23.56 kJ/m,the temperature for the system to lose 1% mass (t1%) is 300 ℃,and that for the system to lose 50% mass (t50%) is 378 ℃. Compared with those of TDE-85/MeTHPA resin,the tensile strength,impact strength,t1% and t50% of the PU-modified resin increases by 48%,115%,30 ℃,11 ℃,respectively. The PU-modified TDE-85/MeTHPA resin has the structure characteristics and properties of interpenetrating polymer networks.