Magnetocaloric properties of phenolic resin bonded La(Fe,Si)13-based plates and its use in a hybrid magnetic refrigerator

We present a simple hot press-based method for processing La(Fe,Si)13-based compounds consisting of La–Fe–Co–Si–C particles and phenolic resin. The magnetic entropy change △S per unit mass for the La Fe_(10.87)Co_(0.63)Si_(1.5)C_(0.2)/phenolic resin compounds have nearly the same magnitude with the base materials. With the content of phenolic resin of 5.0 wt%, the compound conductivity is 3.13 W·m^(-1)·K^(-1). In order to measure the cooling performance of La(Fe,Si)13-based compounds,the La(Fe_(11.6-x)Co_(x))Si_(1.4)C_(0.15)(x =0.60, 0.65, 0.75, 0.80, 0.85)/phenolic resin compounds were pressed into thin plates and tested in a hybrid refrigerator that combines the active magnetic refrigeration effect with the Stirling cycle refrigeration effect. The test results showed that a maximum cooling power of 41 W was achieved over a temperature span of 30 K.

In-situ reactive compatibilization of HDPE/GTR blends by dicumyl peroxide and phenolic resin without catalyst

In-situ reactive compatibilization of high-density polyethylene （HDPE）/ground tire rubber （GTR） blends by dicumyl peroxide （DCP） and HY-2045 - a kind of thermoplastic phenolic resin without catalyst was investigated by studying the mor-phology, stress and strain behavior, dynamic mechanical properties and crystallization performance of the blends. Scanning e-lectron microscopy （SEM） results show that there are a lot of fibrous materials distributing in the interface, which connects the dispersed phase with the matrix and obtains better interfacial strength for prominent mechanical properties. The addition of compatibilizers results in the decrease of crystallinity of the blends and the disappearance of an obvious yield phenomenon, which was proved by the differential scanning calorimeter （DSC） test and X-ray diffraction （XRD） characterization Although the crystallinity of the blends decreases,the tensile strength and tensile strain of the blends significantly increases, especially for the HDPE/GTR/DCP/HY-2045 blends, which is possibly attributed to the good compatibility of the blends owing to the in-situ interface crosslinking. In addition, it is found that the compatibilizing HDPE/GTR blends shows a higher tan^ peak temperature and a broaden transition peak for GTR phase.

Structural Characteristics of Mesophase Spheres Prepared from Coal Tar Pitch Modified by Phenolic Resin

Mesocarbon microbeads （MCMB） were prepared from coal tar pitch modified by phenolic resin and from the same pitch modified by phenolic resin and hexamethylenetetramine at 440℃ for lh. By investigating the morphology of mesophase spheres and the structure of the MCMB carbonized at 1000℃ for lh using scanning electron microscope （SEM） and XRD, it was found that phenolic resin accelerated the formation and coalescence of mesophase spheres. Some of the obtained MCMB were hi- or tri-spheres with the distorted microtextural carbon layers. Hexamethylenetetramine in the pitch modified by phenolic resin accelerated the condensation of phenolic resin and consequently expedited the combination of mesophase spheres, which was proved by the formation of some tetra-spheres. Owing to the cross-linkage of the additives, MCMB with complex structure were obtained.

Synthesis, Properties and Application of a Novel Epoxidized Soybean Oil-toughened Phenolic Resin

A novel epoxidized soybean oil-toughened-phenolic resin(ESO-T-PR)has been synthesized by etheri- fication graft and multi-amine curing ESO.Fourier transform infrared spectroscopy(FTIR)was adopted to investi- gate its molecular structure and scan electron microscope(SEM)was used to observe the micro morphology of its impact fracture surface.This ESO-T-PR was adopted as the matrix resin to prepare paper copper clad laminate (P-CCL)and the properties of resulting P-CCL are found superior to the related Chinese National Standard.The toughing mechanism was investigated by comparing the impact strength,solderleaching resistance,flexural strength, peeling strength and morphology of this ESO-T-PR with those of other two ESO modified phenolic resins.It is demonstrated that during the synthesizing process of ESO-T-PR,the phenol hydroxyl is etherified by ESO or ESO epoxy resin prepolymer(ESO chain extension polymer)and the long ESO epoxy resin chain segments enhance the crosslink density of ESO-T-PR and consequently improve the impact toughness and solderleaching resistance of P-CCL made of ESO-T-PR.The ESO-T-PR is a cheap matrix resin with excellent properties to make P-CCL(elec- tric guide board).

Preparation and Properties of Phenolic Resin/Montmorillonite Intercalation Nanocomposites

Phenolic resin/montmorillonite intercalation composites were prepared by using the methods of pressing intercalation and melt intercalation.Properties and structure of the composites were investigated by using XRD,TG and test of softening point.It is indicated that both the pressing intercalation and melt intercalation can be used to prepare the phenolic resin/organo-montmorillonite intercalation nanocomposites.Compared with phenolic resin,the intercalation nanocomposites have better heat-resistance,higher decomposition temperatures and less thermal weight-loss.However,these two intercalation methods have different effects on the softening point of the intercalation nanocomposites.Pressing intercalation almost does not affect the softening point of the intercalation nanocomposites,while melt intercalation significantly increases the softening point of the intercalation nanocomposites, probably due to the chemical actions happening in the process of melt intercalation.

Synthesis of benzoxazine-based phenolic resin containing furan groups

A novel benzoxazine-based phenolic resin containing furan groups（PFB） was synthesized via simple two-step reactions and the structure of PFB was confirmed by FTIR and ~1H NMR spectra.Differential scanning calorimetry（DSC） showed that the polybenzoxazine cured from PFB had good heat resistance and lower polymerization temperature compared with that of benzoxazine-based phenolic resins.

STUDY ON THE THERMODYNAMIC PROPERTIES OF ADSORPTION OF ETHYL BENZOATE AND DIETHYL PHTHALATE BY PHENOLIC RESIN ADSORBENTS

This paper presents experimental observations on the adsorption of individual solutes by a simple thermodynamic framework, and the equilibrium adsorption of ethyl benzoate and diethyl phthalate on phenolic resin adsorbent in hexane solutions within the temperature range of 293-313 K. The experimental results show that the Freundlich adsorption law is applicable to the adsorption of ethyl benzoate and diethyl phthalate on the adsorbent, since all the correlative factors R' are larger than 0.99. The negative values of all the isosteric adsorption enthalpies for ethyl benzoate and diethyl phthalate indicate that they undergo exothermic processes, while their magnitudes (19-28 kJ/mol) manifest a hydrogen bonding sorption process. Other thermodynamic properties: the free energy changes and the entropy change associated with the adsorption have been calculated from the Gibbs adsorption equation and the Gibbs-Helmholtz equation

Curing mechanism of alkaline phenolic resin with organic ester

To study the curing mechanism of alkaline phenolic resin with organic ester, three esters were chosen to react with three systems - alkaline phenolic resin, potassium hydroxide aqueous solution containing phenol, and potassium hydroxide aqueous solution. The variations of pH, heat release and gel pH during the reactions were monitored and measured. Infrared spectroscopy （IR） and thermal gravity analysis （TG） techniques were used to characterize the curing reaction. It was found that organic ester is only partial y hydrolyzed and resin can be cured through organic ester hydrolysis process as wel as the reaction with redundant organic ester. The sequential curing mechanism of alkaline phenolic resin cured by organic ester was identified as fol ows： a portion of organic ester is firstly hydrolyzed owing to the effect of the strong alkaline; the gel is then formed after the pH decreases to about 10.8-10.88, meanwhile, the redundant organic ester （i.e. non-hydrolysis ester） starts the curing reaction with the resin. It has also been found that the curing rate depends on the hydrolysis velocity of organic ester. The faster the hydrolysis speed of the ester, the faster the curing rate of the resin.

Application conditions for ester cured alkaline phenolic resin sand

Five organic esters with different curing speeds:propylene carbonate(i.e.high-speed ester A);1,4-butyrolactone;glycerol triacetate(i.e.medium-speed ester B);glycerol diacetate;dibasic ester(DBE)(i.e.lowspeed ester C),were chosen to react with alkaline phenolic resin to analyze the application conditions of ester cured alkaline phenolic resin.The relationships between the curing performances of the resin(including pH value,gel pH value,gel time of resin solution,heat release rate of the curing reaction and tensile strength of the resin sand)and the amount of added organic ester and curing temperature were investigated.The results indicated the following:(1)The optimal added amount of organic ester should be 25 wt.%-30 wt.%of alkaline phenolic resin and it must be above 20 wt.%-50 wt.%of the organic ester hydrolysis amount.(2)High-speed ester A(propylene carbonate)has a higher curing speed than 1,4-butyrolactone,and they were both used as high-speed esters.Glycerol diacetate is not a high-speed ester in alkaline phenolic resin although it was used as a high-speed ester in ester cured sodium silicate sand;glycerol diacetate and glycerol triacetate can be used as medium-speed esters in alkaline phenolic resin.(3)High-speed ester A,medium-speed ester B(glycerol triacetate)and low-speed ester C(dibasic ester,i.e.,DBE)should be used below 15°C,35°C and 50°C,respectively.High-speed ester A or lowspeed ester C should not be used alone but mixed with medium-speed ester B to improve the strength of the resin sand.(4)There should be a suitable solid content(generally 45 wt.%-65 wt.%of resin),alkali content(generally 10 wt.%-15 wt.%of resin)and viscosity of alkaline phenolic resin(generally 50-300 mPa·s)in the preparation of alkaline phenolic resin.Finally,the technique conditions of alkaline phenolic resin preparation and the application principles of organic ester were discussed.

PREPARATION AND PHOTOSENSITIVITY OF WATER SOLUBLE PHENOLIC RESINS CONTAINING ACRYLOYL AND QUATERNARY AMMONIUM CHLORIDE GROUPS

New water soluble and photocrosslinkable prepolymers containing acrylate and quaternary ammonium salt groups were synthesized from epoxy phenolic resin via ring-opening reaction with acrylic acid and with aqueous solution of triethylamine hydrochloride successively. The second reaction needs no phase transfer catalyst to accelerate, since the product formed can act as a phase transfer catalyst. The prepolymer obtained contains both photocrosslinkable acrylate groups and hydrophilic quaternary ammonium salt groups. Optimum conditions for these reactions were studied. The photosensitivity of the prepolymer was also investigated. The effects of different photoinitiators, different crosslinkable diluent monomers and amine accelerator on the photosensitivity of the prepolymer were compared. The photoinitiator of hydrogen abstraction type is still effective without using amine or alcohol as accelerator, because the prepolymer contains a H beside the OH groups formed in the ring-opening reactions.

Preparation of montmorillonite modif ied phenolic resin for shell process

The development of montmorillonite modified phenolic resin under microwave irradiation heating was investigated.The effect of montmorillonite content and stirring time on the structure and morphology of synthetic resin was analyzed.The optimum processing procedure was found to be 45 min stirring time with 5.4% montmorillonite addition.Further,the platelet spacing increases with stirring time till montmorillonite exfoliated to nanoscales platelet.When montmorillonite is exfoliated,layered structure at nanoscale can be uniformly distributed in the resin.The overall performance of montmorillonite modi fied phenolic resin is improved remarkably,such as flow ability,tensile strength and toughness property of resin coated sand.However,the gelation speed decreased slightly by adding montmorillonite.

Ceramification of Composites of MgO-Al_(2)O_(3)-SiO_(2)/Boron Phenolic Resin with Different Calcine Time

The ceramifiable polymer composite of MgO-Al_(2)O_(3)-SiO_(2)/boron phenolic resin(MAS/BPF)with 40wt%of inorganic fillers was calcined at 1200℃for different time to promote ceramification of ceramifiable composite and improve heat resistance.The effects of different calcine time on the macroscopical morphology,mass loss,phase evolution,microstructure and chemical bond evolution of MAS/BPF composites were characterized by XRD,XPS,and SEM analyses.The experimental results reveal that the increase of calcine time result in the fewer holes,relatively denser and smoother top layer of MAS/BPF composites and protect the interior from deeper decomposition.The final residues of composites are amorphous carbon and C-O-Si-Al-Mg ceramic.And MAS/BPF composites show excellent mass stability,low shrinkage and self-supporting features after 2 h holding compared with BPF composites without 40wt%of inorganic fillers.

Preparation of Phenolic Resin/Silver Nanocomposites via in-situ Reduction

Resol type phenolic resin/silver nanocomposite was prepared by in-situ reduction method, in which the curing of phenolic resin and the formation of silver nano-particles took place simultaneously. The silver ions were reduced completely to silver nanoparticles, which were dispersed homogeneously in the resin matrix with narrow size distribution.

Fluxing Agents on Ceramification of Composites of MgO-Al2O3-SiO2/Boron Phenolic Resin

Fluxing agents of zinc borate, antimony oxide, galss frit A and glass frit B, with different melting or softening point temperatures, were added into MgO-Al_2O_3-SiO_2/boron phenol formaldehyde resin（MAS/BPF） composites to lower the formation temperature of eutectic liquid phase and promote the ceramification of ceramifiable composites. The effects of fluxing agents on the thermogravimetric properties, phase evolution, and microstructure evolution of MAS/BPF composites were characterized by TG-DSC, XRD and SEM analyses. The results reveal that the addition of a fluxing agent highly reduces the decomposition rate of MAS/BPF composites. Fluxing agents lower the formation temperatures of liquid phases of ceramifiable MAS/BPF composites obviously, and then promote the ceramification and densification process. The final residues of composites are ceramic surrounded by large amount of glass phases.

Synthesis and Properties of Novel Epoxidized Soybean Oil-modified Phenolic Resin /Montmorillonite Nanocomposites

The novel epoxidized soybean oil-modified-phenolic resin/clay nanocomposites（ESO-M-PR/ CN） was prepared. The coupling agent-benzyldimethylphenylammonium chloride [C6H5CH2N^＋（CH3）2C6H5Cl^- , B2MP] was adopted to modify the interface between the organic and inorganic phases. The effect of the nanocomposite structure on its physical and chemical properties was discussed. During the synthesizing process of ESO-M-PR/CN, the phenol hydroxyl was etherified by ESO or ESO epoxy resin prepolymer to provide long ESO epoxy segments. Long ESO epoxy resin chain segments enhanced the crosslink density of ESO-M- PR/CN. The thermal and mechanical properties exhibit a significant improvement. The temperature at which a weight loss of 5% occurs increases from 287.1 ℃ to 402.3 ℃. The flexural strength increases by 25%, while the flexural modulus increases by 39%. Moreover, the properties of resin were enhanced by the effect of the inorganic nanoparticles, while the size of the nanomontmorillonites in the phenolic resin was characterized with a scanning electron microscope. The particle size of inorganic montmorillonites in the modified system is less than 100 nm.

Effect of KCI on Growth of Carbon Fibers During Carbonization of Phenolic Resin

Effects of the KCI additions （1%, 3%, 5% and 7% of the phenolic resin mass ） on phase composition and microstructure of the resin carbon and the growth mechanism of carbon fibers were investigated by using commercial liquid phenolic resin as carbon source and micron-scaled KCl us catalyzer, mixing, hexamethylene- tetramine solidification treating, carbon-embedded firing at 1 000 ℃ for 3 h in order to accelerate the graphitization of phenolic resin during carbonization. The results show that the graphitization degree of resin carbon is im- proved by catalysis of KCl, numerous carbon fibers with 30 - 200 nm in diameter and 10 - 20 μm in length and sheet-like carbon in situ grow in resin carbon. The opti- mal addition of KCl is 5% when lots of carbon fibers can be found in resin carbon, and doo2 diffraction peak of graphite appears obviously in the XRD pattern. The growth mechanism of carbon fiber is that the molten KCl at high temperatures absorbs carbonaceous gas from the decomposition of phenolic resin, accelerating the diffu- sion of solid C atoms in liquid KCl ; after the dissolution of C saturates, carbon atoms separate continuously in lo- cal parts to form carbon fibers or flakes ; meanwhile, the concentration gradient formed by local carbon atoms in the melt offers growth drive for the separation of carbon fibers or flakes on KCl surface.

Preparation of Intercalated Clay/Phenolic Resin Nanocomposites under High Pressure

High pressure method was ased for the first time to produce rectorite clay （REC）/phenolic resin （PF） and organic rectorite clay （OREC） /phenolic resin and montmorillonite（ MMT）lphenolic resin （PF） nanocomposites. The structure of the material phase was studied by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, Fourier transform infrared （ FT- IR ） spectroscopy, thermogravimetric analysis （ TGA ）, and atomic force microscopg＂ （AFM）. The experimental results show that intercalated clay/resin nanocomposites could form under normal temperature and high pressure conditions by the intercalation of polymeric molecules rather than interlayer polymerization.

Chaos Analysis of Discharge Current Based on Tracking Test of Phenolic Resin

In tracking test, discharge is a complicated process and comparative tracking index (CTI) has wide varia-tion. To evaluate tracking resistance, the chaos analysis of discharge current is presented based on the tracking test of phenolic resin in accordance with IEC60112. According to the characteristics of statistical self-similarity and complexity of discharge current, the largest Lyapunov exponent is calculated, and the 2-dimensional attractor of discharge current is reconstructed. Moreover, the attractors of discharge current and recurrence plots of different discharge states are reconstructed. The results indicate that the chaos attractors have different characteristics in evo-lutionary tracks, the topological structure and grain direction of recurrence plots show significant differences. The chaos attractor can describe the tracking process, the recurrence plot can identify the tracking state clearly, while its arithmetic is simple.

STUDY ON THE OXIDIZED GRAPHITE MATERIAL COATED WITH N-DOPED PHENOLIC RESIN FOR LITHIUM ION BATTERIES

Carbon-coated oxidized graphite has been prepared by a liquid-state deposition method. Oxidized graphite wasprepared by wet chemical oxidation. Oxidation increases the reversible capacity of graphite, but its initial charge anddischarge efficiency was reduced. Phenolic resin was applied to form the disordered carbon layer on the oxidized graphite.The efficiency and reversible charge capacity were obviously increased. The morphology of carbon materials wasinvestigated by SEM.

Studies on Thermodynamic Properties of Adsorption of Theophylline by Phenolic Resin Adsorbents

In the present work,the equilibrium adsorption of theophylline was studied by phenolic resin adsorbents: JDW\|2(made by ourselves) and Duolite S\|761 within a temperature range of 303\_323 K. The experimental results show that the Freundlich adsorption law is applicable to the adsorption of theophylline on the two adsorbents,the exponents \%n\%>1 indicate that they are favorable to the adsorptions;the negative values of all the isosteric adsorption enthalpies for the theophylline indicate the exothermic process of the adsorption,while the range(10\_40 kJ/mol) of their magnitudes manifests the physisorption process;other thermodynamic properties,the free energy changes and the entropy change associated with adsorption have been calculated from the Gibbs adsorption equation and the Gibbs\|Helmholtz equation.