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.

Effect of benzoxazine resin on mechanical properties of nitrile rubber composites: Experiment and molecular simulation

Benzoxazine resin,being a new type of phenolic resin deve-loped to overcome the shortcomings of traditional phenolic resins,has been synthesized from phenol,formaldehyde and amine,and does not require solvent elimination or monomer purification to obtain a relatively clean precursor.It has potential application in the field of aerospace due to its low expansion coefficient,high weather resistance,high carbon yield,good mechanical strength,and excellent ablation resistance[1].It can be mixed with various other resins or polymers to produce new resins with a broad range of applications[2-3].

Curing Process of Phenol Formaldehyde Resin for Plywood under Vacuum Conditions

The study characterized the curing behaviors of phenol formaldehyde(PF)resin under different vacuum degrees and explored the properties of 9-ply plywood panels hot-pressed under both vacuum and atmospheric conditions.The changes in core temperature and moisture content of the plywood mats during hot pressing were investigated as well.It was found that the gel times and gel temperatures of PF resin decreased with the increase of vacuum degree using a self-made device.FTIR spectra indicated the degree of polycondensation of hydroxymethyl gradu-ally increased with the increase in temperature.It was also observed that a higher degree of vacuum led to a slower polycondensation reaction rate of PF resin.During different hot-pressing processes,the bonding strengths in the innermost and uppermost gluelines of the vacuum hot-pressed plywood panels were up to 30%–50%higher than their counterparts of conventional hot-pressed products.A less difference in the bonding strengths between these two gluelines was also observed for vacuum hot-pressed products.In addition,the core of vacuum hot-pressed plywood was found to have a greater heating rate and higher temperature at thefinal stage of hot pressing,which was beneficial to cure the PF resin.The results from this study indicate a promising potential of introducing a vacuum during hot pressing to improve the quality and productivity of plywood products and provide a basis for adopting vacuum to hot press wood composites.

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.

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.

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

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 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 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.

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.

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.

The Synthesize and Property Evaluation of High Temperature Resistant Phenolic Resin-Type Profile Control Agent

Most of the mining method of domestic oilfield is waterflood development, thus the water content in the mid and late water flooding would rise faster, and the oil recovery rate would decline relatively more rapid. So it is very important to research profile control agent for stabilizing oil production resin-type profile control agent, and focus on researching the themal stability, shear resistance, gelation time and gelation strength and other properties of this profile control agent?[1]. Finally, the best ratio for synthesizing the high temperature resistant phenolic resin-type profile control agent was obtained.

Enhanced Thermal Conductivity of Carbon Nanotube Arrays by Carbonizing Impregnated Phenolic Resins

A carbonization method is reported to improve the thermal conductivity of carbon nanotube (CNT) arrays. After being impregnated with phenolic resins, CNT arrays were carbonized at a temperature up to 1400°C. As a result, pyrolytic carbon was formed and connected non-neighboring CNTs. The pyrolysis improved the room temperature conductivity from below 2 W/m·K up to 11.8 and 14.6 W/m·K with carbonization at 800°C and 1400°C, respectively. Besides the light mass density of 1.1 g/cm3, the C/C composites demonstrated high thermal stability and a higher conductivity up to 21.4 W/m·K when working at 500°C.

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.

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.

Mechanical Properties of Phenolic-Resin Composites Reinforced with CF/BF Interlayer Hybrid Fibers

Phenolic-resin composites reinforced with carbon fiber（CF） and basalt fiber（BF） interlayer hybrid fibers plain fabric were fabricated.The tensile strength,compressive strength and interlaminar shear strength of the prepared composites were studied.The results indicated that hybrid fibers reinforced composites possessed the advantages of both CF and BF.When resin content was 35% by volume fraction,the comprehensive mechanical performance of BF/CF reinforced phenolic resin composites reached the optimal values with the warp and weft direction tensile strength,compressive strength and interlayer shear strength being 252 MPa and 487 MPa,105 MPa and 129 MPa,21 MPa and 20 MPa,respectively.The scanning electron microscope（SEM） observations showed that the BF/CF hybrid fibers reinforced composites had better interfacial adhesion.

Fabrication and Properties of SiB6-B4C with Phenolic Resin as a Carbon Source

Si-B-C ceramic composites were synthesized using SiB-6,B-4C,and phenolic resin as a carbon source by pressureless sintering in an Ar atmosphere.Then,the Si-B-C ceramic composites were fabricated to determine their potential for applications as high hardness and high temperature composites.The X-ray diffraction patterns of sintered bodies of SiB-6-B-4C with carbonized phenolic resin can be seen that SiB-6 and C changed to B-4C and SiC.In this study,it is obtained that carbonized phenolic resin is good addition material as a reaction material comparing to carbon powder at 1683 K for 1 h by pressureless sintering in an Ar atmosphere.

Evolution of Physical and Chemical Properties of Phenolic Resin-Based Carbon/Carbon Composites Reinforced with Short Discrete Fibers during Pyrolysis

In the present work, novolac phenolic resin-based composites reinforced with short discrete carbon fibers were pyrolized at different temperatures from 400℃ to 900℃. Their physical and chemical properties were studied, linterfacial bonding between the matrix and carbon fiber and its influence on mechanical properties of analyzed composites were analyzed. Experimental results demonstrated strengthening of interfacial bonding with increase of pyrolysis temperature. Evolution of failure behavior was observed.

Simulation on Pyrolysis Products of Thermoset Phenolic Resin with Different Chemical Structure and Experimental Validation

The simulation on pyrolysis products of pure PF resin with different chemical structure was investigated and validated by pyrolysis gas-chromatography mass spectrometry(Py-GC/MS).The simulation of pyrolysis products of phenolic resin with different chemical structure was investigated by AMBER(Assisted Model Building with Energy Refinement)force field.The content of pyrolysis products phenol and cresol decreases with the increase of F/P(formaldehyde/phenol)value.The content of pyrolysis products dimethylphenol and trimethylphenol increases with the enhancement of F/P value.The crosslink density of phenolic mixture can be measured by the content of pyrolysis products dimethylphenol and trimethylphenol.Consequently,the results of simulation were validated by the Py-GC/MS experiment.

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.