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Polyether ether ketone (PEEK) oligomers were synthesized through a solution reaction using sulfolane as a solvent, the resultant oligomers were employed to synthesize high melt viscosity PEEK through solid-state polymerization in a twin-roller mixer. The effects of polymerization time on the crystallization properties, thermal properties and flowability of PEEK were investigated. The results indicated that both the degree of crystallinity and crystallization completeness of PEEK decreased with an increase in polymerization time. The degree of crystallinity of PEEK after polymerization for 5 h decreased by about 31. 4 % as compared to that of the oligomers. All samples possessed residual weights greater than 50 % at 900 °C, indicating outstanding thermal stability. In addition, the melt viscosities of PEEKs increased significantly with an increase in the polymerization time, and it reached approximately 13-360 times as high as that of oligomers. [ABSTRACT FROM AUTHOR]

In order to solve the problems that the phase change temperature of fatty acid is higher than the building application requirements, and the existing fatty acid microencapsulated phase change materials have low encapsulation rate and low latent heat, the binary phase change material capric acid-stearic acid was first prepared in this paper. The thermal properties results show that the phase change temperature and latent heat of phase change of capric acid-stearic acid are 24.28 ℃ and 178.21 J/g, which meet the building application requirements. On this basis, CA-SA@SiO2 MPCM (microencapsulated phase change materials) with different core wall mass ratio were prepared by sol-gel method of capric acid-stearic acid with silica as the outer wall material. Micro morphology, particle size, thermal properties, chemical stability and anti-seepage performance of the MPCM were characterized. The results show that core wall mass ratio directly affects the properties of the MPCM. The optimal core wall mass ratio is 50: 50. The MPCM is spherical, smooth and dense, the particle size ranges from 2 to 500 μm, and the mainly concentrated below 50 μm. The wall material covers the core material only by physical action, and the thermal stability of phase change core material can be improved after microencapsulation. Moreover, the thermal decomposition temperature is significantly higher than the use environment of the wall material. The equilibrium leakage rate is only 4.53%, and the phase change temperature is 24.63 ℃, which is within the comfort range of human body. The latent heat of phase change and encapsulation rate is 138.16 J/g and 77%, respectively. It effectively solves the problems of high phase change temperature, low encapsulation rate and low latent heat of phase change, and provides a new material compatible with suitable temperature zone, high energy efficiency density and high stability for phase change energy storage building envelopes. [ABSTRACT FROM AUTHOR]

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In order to investigate the changes in structure and properties of waxy maize starch (WMS) after its nano-starch was prepared by pullulanase enzymolysis-dynamic high pressure micro-fluidization technology (P-DHPM), this paper explored the trends of changes in starch microstructure, crystalline structure, molecular structure, particle size, molecular weight, and thermal properties before and after the treatment. The results showed that spherical starch particles were turned into fragmentization, and the crystalline structures were transferred into amorphous states, the short-range ordered structure was increased, and the molecular weight of starch was decreased with the increment of enzymatic hydrolysis time. In the meantime, the peak gelatinization temperature (Tp) of treated starch was decreased from 71.23 ℃ to 55.81 ℃, and the enthalpy value of pasting (ΔH) was decreased to 4.68 J/g significantly (P

Copyright of Cotton Textile Technology is the property of Cotton Textile Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nanocomposite films were prepared by melting and blending nano-MICA powder modified with polylactic acid (PLA), polybutylene adipate-co-terephthalate (PBAT) and aluminate coupling agent. The properties of nanocomposite films were characterized by a Fourier transform infrared spectroscopy (FTIR), a water vapor transmittance tester, an oxygen transmittance tester, and TG-DSC synchronous thermal analysis instrument. The safety of nanocomposites was evaluated by total migration experiments and gas chromatography-mass spectrometry (GC-MS) to determine the specific migration of nanocomposites. The results show that the aluminate coupling agent successfully activates the nano-MICA powder. The glass transition temperature of PLA can be increased by modified nano-MICA powder, while the crystallinity of PLA first increases and then decreases, and the addition of 0.2% modified nano-MICA powder has the best effect. The thermal stability of the PLA/PBAT system decreases slightly with the increase of the amount of modified nano-MICA powder. The addition of 0.2% modified nano-MICA powder reduced the water vapor transmission coefficient of the film by 28%. The addition of nano-MICA powder enhances the interface roughness of the film, and the addition of modified nano-MICA powder can still meet the safety requirements as a food contact material. [ABSTRACT FROM AUTHOR]

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Aerogel/fiber composites have shown a wide range of applications in aerospace, defence, environmental management and biomedicine due to their high porosity, low bulk density, high specific surface area and low thermal conductivity.The thermal and mechanical properties and interfacial compatibility of aerogel/fiber composites was reviewed, the heat transfer mechanism, mechanical property enhancement mechanism and interfacial compatibility bonding mechanism was introduced, and the effect of different fiber embedding on the final properties of the composites considering different fiber volume fractions and fiber multiscale i.e. different fiber diameters (aspect ratio) and pore diameters between fibers was summarized in this paper. Finally, the prospective future of the research directions of aerogel/fiber composites were proposed, including heat resistance, improved mechanical properties and material interface bonding.

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旨在为全氢化硬脂在塑性脂肪、油凝胶等的应用提供一定的开发依据和理论基础，全面分析硬脂组成对其晶体性质的影响。测定了全氢化棕榈仁油（HPKO）、全氢化棕榈油（HPO）、全氢化棉籽油（HCSO）、全氢化大豆油（HSO）、全氢化低芥酸菜籽油（HCO）、全氢化高芥酸菜籽油（HRO）、精炼漆蜡（LW）、可可脂（CCB）的脂肪酸与甘三酯组成、热性质、微观结构及形态，研究硬脂的组成对其热性质、微观结构及形态的影响。结果表明：HPO、HCSO、HSO、HCO均以棕榈酸和硬脂酸为主，HPKO以月桂酸和豆蔻酸为主，HRO以硬脂酸和山嵛酸为主，LW以棕榈酸和油酸为主，CCB以硬脂酸、油酸、棕榈酸为主；硬脂的甘三酯组成对其熔点有很大影响，CCB、HPKO的熔化温度较低，HSO、HCO、HRO的熔化温度较高；HRO虽然含有大量的山嵛酸，但其熔化温度低于HSO和HCO，这可能与甘三酯间的相互作用有关；油脂中高熔点甘三酯含量影响油脂的固体脂肪含量曲线，相同温度下高熔点甘三酯含量高的油脂具有更高的固体脂肪含量，甘三酯间的相互作用也会影响油脂的固体脂肪含量曲线；CCB晶型为β型，HPKO、HPO、HCSO为β′型，HCO、HSO、HRO则为α型，LW为β和β′混合晶型；油脂的甘三酯组成会影响结晶聚集体的形态，高熔点甘三酯含量越高，结晶聚集体越致密有序；测定条件下（25 ℃）油脂的固体脂肪含量也会影响结晶聚集体形态。 In order to provide certain development basis and theoretical basis for the application of full hydrogenated stearin in plastic fats and oleogels, the influence of stearin composition on its crystal properties was analyzed, the fatty acid and triacylglycerols (TAGs) compositions, thermal properties, microstructure and morphology of hard fats, including fully hydrogenated palm kernel oil (HPKO), fully hydrogenated palm oil (HPO), fully hydrogenated cottonseed oil (HCSO), fully hydrogenated soybean oil (HSO), and fully hydrogenated canola oil (HCO), fully hydrogenated rapeseed oil (HRO), refined lacquer wax (LW) and cocoa butter (CCB) were determined, and the effects of composition of these stearin on their thermal properties, microstructure and morphology were investigated. The results showed that the major fatty acids of HPO, HCSO, HSO and HCO were palmitic acid and stearic acid. Lauric acid and myristic acid were the major fatty acids of HPKO. HRO was mainly composed of stearic acid and behenic acids. LW contained large amount of palmitic acid and oleic acid. The major fatty acids of CCB were stearic acid, oleic acid and palmitic acid. The melting points of these stearin were influenced greatly by their TAGs composition. The melting points of CCB and HPKO were lower relatively, and the melting points of HSO, HCO and HRO were higher. Although HRO contained a lot of behenic acid, its melting point was lower than that of HSO and HCO, which was related to the interaction of TAGs. The content of TAGs with high melting point affected the solid fat content (SFC) profile of the stearin. At the desired temperature, the higher the content of TAGs with high melting points in stearin, the higher the SFC of stearin. SFC profile of stearin was also affected by the interaction of TAGs in them. The crystals in CCB was β form,HPKO, HPO and HCSO were β′ form,HCO, HSO and HRO were α form, LW was a mixture of β and β′ form. The morphology of the crystalline aggregates was affected by TAGs composition in stearin, the higher the content of high melting point TAGs, the denser and more orderly the crystalline aggregates. The SFC of stearin under the determination condition （25 ℃） also influenced the morphology of the crystalline aggregates.

Konjac glucomannan (KGM) and cassava acetylated distarch phosphate ( ADSP ) were used as raw materials, methyl cellulose as emulsifying agent, and soybean oil as oil phase to prepare KGM-ADSP composite emulsion gels. The effects of different freezing treatments on the texture, rheology and thermal properties of KGM- ADSP composite emulsion gels were studied by measuring the color, whiteness, centrifugal loss, ect. of KGM- ADSP composite emulsion gels after different freezing treatments and porcine back fat (control group). The results showed that freezing treatment could significantly improve the whiteness, hardness, elasticity and centrifugal loss of KGM-ADSP composite emulsion gels, and reduce the cooking loss, storage modulus and loss modulus, and no oil melting occurred in KGM-ADSP composite emulsion gels when heating up. The whiteness, texture, hardness, cohesion, chewiness and rheological properties of KGM-ADSP composite emulsion gels after 300 W ultrasonic- assisted freezing treatment were closest to those of porcine back fat. And the differences in storage modulus and loss modulus between KGM-ADSP composite emulsion gels after 300 W ultrasonic-assisted freezing treatment and pig back fat were minimal under certain thermal environment. It could be used as the fat mimetic in hot processed meat products. [ABSTRACT FROM AUTHOR]

In this study, R2O-Bi2O3-B2O3-SiO2 lead-free low-melting point glass was prepared by high temperature melting method and applied to automobile glass enamel. The effect of composition on the structure, thermal properties and acid resistance of glass was studied. The results show that with the increase of Bi2O3/B2O3 and Bi2O3/SiO2, the [BO3] and [BiO3] triangular structural units gradually decrease, the [SiO4] and [BO4] tetrahedral structural units gradually increase, and the network structure of glass is enhanced. When the alkali metal oxide content is 15% (mole fraction), the thermal expansion coefficient α25 ~ 320 °C, transition temperature Tg and softening temperature Tf of double alkali glass are smaller than those of single alkali glass, and the acid mass loss rate Dr is lower. When n(Li2O) : n(Na2O) is 1 : 1, the α25 ~ 320 °C of double alkali glass is 9. 35 ×10-6 °C-1, the Tg value is reduced to 439. 8 °C, the Tf value is 481. 7 °C, and the Dr value is 0. 006 70 g/cm². Applying it to automotive glass enamel, the sintered enamel has good adhesion, blackness, coverage and gloss. [ABSTRACT FROM AUTHOR]

为扩大棉籽油用途，提高其附加值，采用气相色谱、高效液相色谱、低场脉冲核磁共振分析仪、差示扫描量热仪、X-射线衍射仪和偏光显微镜分析了棉籽油改性后的产物棉籽油硬脂（COS）和全氢化棉籽油硬脂（FHCOS）的脂肪酸组成、甘三酯组成、SFC含量、热性质和微观结构。结果表明：COS主要由不饱和脂肪酸和非三饱和的甘三酯组成，FHCOS几乎全部由饱和脂肪酸和三饱和甘三酯组成；随温度升高，COS的SFC不断降低，FHCOS的SFC在温度高于35℃时开始降低，相同温度下FHCOS的固体脂肪含量（SFC）均高于COS的，COS在结晶和熔化过程中均有2个峰，FHCOS有1个峰，FHCOS的熔化和结晶温度均高于COS的；COS在15 ℃时无明确的晶型及稳定的结构，FHCOS为二倍链长堆积的β′晶型，结晶体为针状或棒状，结晶聚集体为类似玫瑰花状。因此，以COS和FHCOS代替棕榈油作为生产起酥油、人造奶油、黄油等的基料油具有一定的开发和应用前景。 To expand the use of cottonseed oil and increase its added value, the fatty acid compositions, triglyceride compositions, solid fat content (SFC), thermal properties and microstructure of cottonseed oil stearin (COS) and fully hydrogenated cottonseed oil stearin (FHCOS) as modified products of cottonseed oil, were analyzed by gas chromatography, high performance liquid chromatography, low field pulsed nuclear magnetism, differential scanning calorimeter, X-ray diffractometer and polarizing microscope, respectively. The results showed that COS mainly consisted of unsaturated fatty acids and non-trisaturated triglycerides, and FHCOS almost entirely consisted of saturated fatty acids and trisaturated triglycerides. The SFC of COS decreased with the increase of temperature, while the SFC of FHCOS decreased as the temperature was higher than 35℃，and the SFC of FHCOS was higher than that of COS at the same temperature, COS had two peaks in both melting and crystallization, while FHCOS had one peak, and the melting and crystallization temperatures of FHCOS were higher than those of COS. COS had no definite crystal form or stable structure at 15 ℃, while the crystal of FHCOS was double chain length-β′ type. The crystal cluster of FHCOS was needle-like or rod-like, the morphology of the aggregates of these clusters was rosette-like. The study indicated that COS and FHCOS, as a base oil replaced palm oil for the production of shortening, margarine, butter has a certain prospect for development and application.

Yb∶CaGdAlO4 (abbreviated as Yb∶CALGO) crystal has partially disordered structure, excellent thermal and spectral properties, broad absorption and emission band, and is suitable to be pumped by the high-power InGaAs laser diode (LD) to achieve high power ultra fast laser. The high nonlinear refractive index coefficient of Yb ∶ CALGO is beneficial to the optimization of its mode-locked laser. The Yb∶CALGO crystal also has the advantages of simple energy levels, low intrinsic quantum defect and high radiation quantum efficiency etc, and thus becomes the new generation of LD pumped femtosecond laser gain medium in recent years, with the advantages of compact structure, high efficiency and low cost etc. This paper provides a brief view of the crystal structure, crystal growth, defect analysis, thermal properties and spectral properties of Yb∶CALGO crystal, and mainly focuses on the recent progress of ultra fast laser technologies based on the research results of Yb∶CALGO crystals, including the mode-locked technologies by the semiconductor saturation absorber mirror and Kerr lens mode-locked ultrafast laser, as well as the regenerative amplifier ultra fast laser technologies. [ABSTRACT FROM AUTHOR]

The characteristics and distribution of the thermal and physical properties of Quaternary strata and red-bed rock in the shallow 200 m of Hefei City were revealed by a comparative analysis of laboratory and field thermal response tests in this study. The results show that the thermal conductivity of the Quaternary and red beds in the strata with depths shallower than 200 m in Hefei increased from 2.1~2.8 W/(m·K). There are two closed-loop peak areas (2.8 W/(m·K)) in the northwest and southeast of Hefei City. The volumetric heat capacity increased from 2.1~2.7 MJ/(m³ ·K) gradually from northwest to southeast, which is consistent with the direction of groundwater runoff. The average value of thermal conductivity in different strata was as follows: Quaternary System (1.56 W/(m·K)) < Cretaceous System (1.69 W/(m·K))

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Using trans-polyisoprene （TPI） as matrix, the effects of nano SiC amount on curing characteristics, physical and mechanical properties, thermal properties and shape memory properties of SiC/TPI shape memory composites were studied. The results showed that with increase of SiC amount,the scorch time and curing time of the composites decreased gradually, tensile strength increased firstly and then decreased, and hardness increased gradually. The crystallinity of the composites decreased gradually from 16.5% to 13.9% as SiC amount increased from 0 to 20 phr (mass, the same below). The one-way shape memory property of the composites was the best when the amount of SiC was 10 phr, and the shape recovery rate of the two-way shape memory behavior reached the maximum value of 79.1% when the stress was 250 kPa.

Polybutylene succinate (PBS) and a series of multi-block hydroxyl-terminated diol copolymers were synthesized by a "one-step"method with succinic anhydride (SAA) and 1,4-butanediol (BDO) as monomers, and terminal hydroxy diols as copolymer monomer. The condensation product of phenolphthalein and SAA was used to participate in the copolymerization of SAA and BDO, and biodegradable triblock polyester thermoplastic elastomers with rigid and flexible chain segments, poly(butylene succinate-co-phenolphthalein butylene succinate) (SAA-PHE-PBS), were prepared by the chain modulation synthesis method. The molecular weight, chemical structure composition, thermal properties and crystallization property of PBS and its copolymers were investigated, and their biodegradability was tested with Candida antarctica lipase B. The results showed that the glass transition temperature of multi-block hydroxyl-terminated diol copolymer did not change much, the melting tempe-rature did not change significantly, the crystallinity decreased, the hydrophilicity was improved, and the biodegradability was greatly improved. The glass transition temperature of the triblock thermoplastic elastomer SAA-PHE-PBS was elevated, the crystallinity was not much different from that of PBS, the hydrophobicity was stronger than that of PBS, resi-dual mass fraction of SAA-PHE-PBS increased, and the biodegradability showed different degrees of decline.

毛漆蜡酸值高、色泽深，需要通过精炼提高其品质。对毛漆蜡进行脱酸、脱色和脱臭处理，对精炼前后漆蜡的酸值、过氧化值、色泽、甘油酯和脂肪酸组成进行了分析，采用X-射线衍射技术对漆蜡晶型进行测定，通过固体脂肪含量的测定和差示扫描量热法分析了漆蜡的热性质。结果表明：脱酸后漆蜡的酸值（KOH）由（35.06±0.05）mg/g降至（0.12±0.01）mg/g；精炼后，漆蜡色泽由深褐色变为乳白色，过氧化值为（0.28±0.04）mmol/kg。精炼过程中漆蜡的甘油酯和脂肪酸组成没有发生改变，但脱酸漆蜡的甘三酯含量显著增加，甘一酯和甘二酯含量显著降低，棕榈酸含量显著增加，油酸和亚油酸含量显著降低;脱色、脱臭对漆蜡的甘油酯和脂肪酸含量没有显著影响。固体脂肪含量分析表明，毛漆蜡的熔化范围为20~55 ℃，脱酸、脱色和脱臭漆蜡熔化范围为30~60 ℃；X-射线衍射数据显示，毛漆蜡以β晶型为主，并存在少量α晶型，精炼后α晶型消失；差示扫描量热分析表明，脱酸、脱色和脱臭漆蜡熔点有所升高。这些变化可能是精炼过程中毛漆蜡中的绝大部分游离脂肪酸、部分甘二酯和一些挥发性物质被除去所致。The crude lacquer wax should be refined to improve its quality because of its high acid value and dark color. The crude lacquer wax was deacidified, bleached and deodorized,and the acid value, peroxide value, color, glycerides and fatty acid composition of lacquer wax before and after refining were analyzed. The crystalline shape of lacquer wax was determined by X-ray diffraction technique, and the thermal properties of lacquer wax were analyzed by solid fat content determination and differential scanning calorimetry. The results showed that after deacidification, the acid value of lacquer wax decreased from (35.06±0.05)mgKOH/g to (0.12±0.01)mgKOH/g; after refining, the color changed from brown to milky white, and the peroxide value was (0.28±0.04) mmol/kg. The glycerides and fatty acid compositions of lacquer wax did not change in the refining process, but in deacidification process, the contents of triglycerides increased significantly, the contents of monoglyceride and diglyceride decreased significantly, and the palmitic acid content increased obviously, while the oleic acid and linoleic acid contents decreased obviously. There was no significant effect of bleaching and deodorization processes on the glycerides and fatty acid contents of lacquer wax. The solid fat content analysis showed that the melting range of crude lacquer wax was 20-55 ℃, and the melting range of deacidified, bleached and deodorized lacquer wax was 30-60 ℃. The X-ray diffraction data showed that the crude lacquer wax was dominated by β-type crystals, and a small amount of α-type crystals existed, while the α-type crystals disappeared after refining. The differential scanning calorimetric analysis showed that the melting points of deacidified, bleached and deodorized lacquer waxes increased. These changes might be due to the removal of most of the free fatty acids, some diglycerides and some volatile substances from the crude lacquer wax during refining.

As an important window for photoelectric information transmission with the outside world under high temperature conditions, high temperature resistant transparent materials are mainly used in emerging fields such as spacecraft, missile, high-temperature and high-pressure container and laser. At present, high temperature resistant transparent materials mainly include high temperature resistant organic materials, crystal materials and tempered glass. Tempered glass is the most commonly used high-temperature resistant transparent material at present. Compared with chemical tempered glass, physical tempered glass has higher temperature resistance, but both have the problem of toughened stress attenuation at high temperature. Typical products of tempered glass include physical tempered alkali-free aluminosilicate glass and chemical tempered lithium aluminosilicate glass. Finally, the author looks forward to the development trend of high temperature resistant transparent materials. [ABSTRACT FROM AUTHOR]

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Copyright of China Plastics / Zhongguo Suliao is the property of Journal Office of CHINA PLASTICS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To improve the dispersibility of the silicon dioxide (SiO2) and investigate the effect of particle size on the properties of matrix, 50, 90 nm and 220 nm nano-SiO2 were prepared by Stöber method, and SiO2 nanofluid (NF) was prepared by grafting the organosilanes and polyether amine on the surface of SiO2nanoparticles. Chemical structure and physical morphology of nanofluid were investigated by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The mechanical properties of SiO2 nanofluid/epoxy resin (NF/EP) composites with different particle sizes and different contents were studied, the results indicate that the mechanical properties of composites are increased first and then decreased with the increase of content. The 50 nm SiO2nanofluid has the best effect on improving impact strength, the impact and bending strength of epoxy resin are enhanced by 54.55% and 11.64% with the 1 phr addition. The 220 nm SiO2nanofluid has the best effect on improving bending properties, the impact and bending strength of epoxy resin are enhanced by 50.00% and 17.51% with the 1 phr addition. The results of the DSC and linear expansion coefficient tests show that the NF/EP composites have higher glass transition temperature and lower linear expansion coefficient than pure epoxy. Thus, with adequate mechanical properties and low coefficient of thermal expansion, NF/EP composites can be considered as promising candidates in the electronic packaging fields.

Ordered core(PEO)-shell(PHB) microfibers were prepared by coaxial electrostatic spinning technology and high-speed rotating receiving roller with polyoxyethylene (PEO)/chloroform solvent as core spinning solution and poly(β-hydroxybutyrate) (PHB)/chloroform solvent as shell spinning solution. The surface morphology, core-shell structure, thermal properties, crystallization properties and mechanical properties of core(PEO)-shell(PHB) microfiber film were characterized and analyzed by SEM, TEM, DSC, TGA, XRD and DMA. The results show that PEO/PHB microfiber has remarkable core-shell structure; fiber arranges in the same direction and the average diameter are 0.57-1.27 μm; the crystal structure of core(PEO)-shell(PHB) microfiber includes α-type crystal of PHB and monoclinic crystal of PEO; when the spinning voltage is increased, the diameter of the fiber decreases, and the crystallinity increases first and then decreases; the fiber diameter increases with the increase of injection speed, and the crystallinity first increases and then decreases; with the increase of the collection distance, the fiber diameter first decreases and then increases, and the crystallinity first increases and then decreases. By changing the single spinning condition, the corresponding fiber films with the spinning voltage of 18 kV, the push velocity of 0.07 mm/min and the collection distance of 8 cm all have high mechanical properties. Compared with pure PHB fiber and PEO fiber, the thermal stability of each component in ordered core(PEO)-shell(PHB) microfiber is improved.

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Copyright of China Plastics / Zhongguo Suliao is the property of Journal Office of CHINA PLASTICS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Research progress and application of stereo-complexed polylactide fibers structure and property were summarized. Crystal structure of stereo-complexed polylactide fiber was introduced. Mechanical, thermal, hydrolysis and dyeing property of stereo-complexed polylactide fiber were analyzed. Applications of stereo-complexed polylactide fiber in fields of textile, medical hygiene, sewage treatment and air filtration were summarized. It is considered that the excellent thermal stability of stereo-complexed polylactide fiber must have higher content and stable stereo-complexed crystals. It is necessary to conduct in-depth basic research on structure and property, crystal structure regulation technology suitable for continuous fiber processing should be developed and researched, industrial application of stereo-complexed polylactide fiber should be promoted. [ABSTRACT FROM AUTHOR]

A bio-based benzoxazine (V-fa) was synthesized from furfuramine, vanillin and paraformaldehyde. Its chemical structure was characterized by Fourier-transformed Infrared spectra (FT-IR) and ¹H-Nuclear Magnetic Resonance (¹H-NMR) spectra. Results show that this new benzoxazine monomer is synthesized successfully. Dicyclopentadiene-phenol epoxy resin (DCPD-ER) was selected as a research object. V-fa was added into DCPD-ER in different proportions as a latent curing agent. At the same time, a usual curing agent, diaminodiphenylmethane (DDM), was also used as a comparative study. The curing reaction of the resin system was studied by Differential Scanning Calorimetry (DSC) and FT-IR spectra. Compared with DCPD-ER/DDM, DCPD-ER/V-fa has a higher initial curing reaction temperature and curing reaction activation energy. DCPD-ER/V-fa can cure at a high temperature, which is attributed to the reaction between phenolic hydroxyl groups produced by ring-opening reaction of the benzoxazine and epoxy groups. In addition, the thermal properties of the cured products were investigated by Dynamic Mechanical Analysis (DMA) and Thermogravimetric Analysis (TGA). The addition of V-fa can improve the heat resistance and thermal stability of the resin system. The glass transition temperature (Tg), initial decomposition temperature and char yield under nitrogen at 800 °C (Yc) of DCPD-ER/V-fa are higher than those of DCPDER/ DDM, and the Tg and Yc can reach as high as 192 °C and 44%, respectively. Moreover, the flame retardancy of DCPDER/ V-fa was evaluated on the basis of the results from TGA measurements. The limiting oxygen index (LOI) of DCPD-ER/Vfa can reach as high as 35.1, suggesting that the addition of V-fa improves the flame retardancy of the epoxy resin. [ABSTRACT FROM AUTHOR]

Poly(butylene succinate) (PBS) and its copolyester with 2-methyl-1, 3-propanediol (MPO) (PBMS) were synthesized through direct esterification-melt polycondensation. The chemical structure and molecular weight of the resultant PBS and its copolyester were characterized by Fourier-transform infrared spectrometry, nuclear magnetic resonance spectrometry (¹H-NMR), and gel permeation chromatograph, and their thermal performance was valuated by differential scanning calorimetry, simultaneous thermal analyzer, and melt flow rate tester. The structural characterization results indicated that there were repeating structural units of butanediol succinate (BS) and 2-methyl-1, 3-propanediol succinate ( MS) in the main chains of the copolyester molecules. The content of MS was almost the same as that of MPO added in the synthetic process, confirming the successful synthesis of the PBMS copolyester according to our design strategy. The weight-average molecular weights of PBS and PBMS were determined to be 7 . 87X104~8. 75X104 g/mol. Thermal analysis results indicated that the glass transition temperature of PBMS gradually increased with an increase in the MPO content but its melting temperature decreassed gradually. Moreover, the non-isothermal crystallization capability of PBMS weakened gradually and its degree of crystallinity decreased from 74. 57 % to 49. 42 %. The thermal degradation temperature of PBMS was higher than 400 °C without any change with a variation of MPO content. AS the content of MPO increased, the melt index of PBMS increased gradually. Compared to pure PBS, PBMS exhibited better melt fluidity at the same temperature. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the development of polyester industrial technology, the mechanical properties of polyester industrial yarn such as strength and modulus have been continuously improved. The application field of composites reinforced with polyester fiber (fabric) has also been expanding because of its advantages such as lightweight, flexibility and good weavability. Among them, polyester fiber (fabric) reinforced polyvinyl chloride ( PVC) flexible composites have been widely used in long,span buildings such as sports buildings, shopping malls, transportation service facilities and so on due to the high strength and modulus, good dimensional stability, strong bearing capacity and excellent fatigue resistance. However, polyester, characterized by smooth surface, lack of polar groups and chemical inertia on the surface, is difficult to excellently bond with PVC matrix, resulting in poor interfacial bonding strength of PVC matrix composites. As a result, polyester fabric / PVC flexible composites have disadvantages such as high water absorption and poor thermal stability in practical application, resulting in proness to going mouldy and poor fatigue resistance of materials. This affects the service life and limits the application to a certain extent. Therefore, it is necessary to study the interface bonding properties of polyester fabric / PVC flexible composites under modified treatment and their relationship with water absorption and thermal properties. In order to investigate the influence of fabric modification treatment on the water absorption and thermal properties of polyester fabric / PVC composites, the polyester fabric was modified by alkali treatment, alkali solution and sizing agent combined treatment, and the polyester fabric / PVC composites were prepared by contact molding technology. Scanning electron microscopy (SEM) was used to observe the section morphology of polyester fabric / PVC composites, and the water absorption fraction and thermal stability of the composites were tested and analyzed. Based on the above, this paper adopted the method of correspondence analysis to investigate the relationship between water absorption and interfacial bond of polyester fabric / PVC composites. It is found that with the increase in surface roughness of alkali treated polyester fabric, the contact area between fabric and matrix is increased, and the interfacial adhesion of composites is improved to a certain extent. Sizing treatment improves the wettability between polyester fabric and PVC matrix, increases the interaction point between polyester fabric surface and PVC matrix, and strengthenes the mechanical locking between polyester fabric and PVC matrix. Therefore, the interface bonding of the composites is improved. Fabric modification reduces the water absorption of polyester fabric / PVC composites, and with the extension of soaking time, the moisture absorption of composites is realized mainly through the capillary action at the interface of composites. There are obvious differences in the moisture absorption laws of unmodified polyester fabric / PVC composites, alkali treated polyester fabric / PVC composites, alkali solution and sizing agent jointly treated fabric / PVC composites, indicating a great difference in the interfacial structures of the three composites. The water absorption mass fraction of unmodified polyester fabric / PVC composites, alkali treated polyester fabric / PVC composites, alkali solution and sizing agent jointly treated fabric / PVC composites decrease successively, indicating their close interface bonding in sequence. Fabric modification has no significant effect on the thermal stability of polyester fabric / PVC composites. The relationship between water absorption and interfacial bond of polyester fabric / PVC composites can bring inspiration for characterization of structural composites. The worse the water absorption property of structural composite, the better the interface bonding property. The results of this research can provide reference for the characterization of structural composites in the future. [ABSTRACT FROM AUTHOR]

The melt crystallization properties, optical properties, molecular weight distribution, mechanical properties, capillary rheological properties, and thermal shrinkage properties of three types of thin-walled injection-molded polypropylenes were investigated. The results indicated that K1860 has the same properties with the commercial PP products, PP1 and PP2, and its molecular weight distribution was narrower than PP1 and PP2. The bending and tensile properties of the K1860 were better than those of PP1 and PP2. The K1860 can completely meet the requirements for the production of large thin-walled injection-molded products. [ABSTRACT FROM AUTHOR]

In order to improve the shortcomings of the finite element unit-cell establish method based on traditional FEM, which has difficulty in meshing and calculation, a superimposed method was proposed. Based on the superimposed method, the finite element unit-cell model of two-dimensional triaxial braided composites was established. Based on the coupling method, the coordination relationship between degree of freedom of element grid of displacement field and temperature field from reinforcement and matrix were given, and the match method of superimposed region thermal properties and the periodic boundary conditions of the unit-cell model temperature field were determined. The equivalent thermal conductivity coefficient and the equivalent thermal expansion coefficient of the unit-cell model were obtained by applying the periodic boundary conditions. Based on this method, the thermal properties of two-dimensional triaxial braided composites were predicted and analysed. The results show that different braiding angles and fiber volume faction have certain effects on the thermal conductivity coefficient and thermal expansion coefficient in different directions.

Polymethacrylimide foams were prepared by free radical bulk polymerization with butyl methacrylate (BMA), acrylamide (AM) as the reactive monomer, acrylic acid (AA) as the third monomer and crosslinker at different heat treatment time. The structure and properties were characterized by FTIR, SEM, TGA and DSC. The results show that with the increase of heat treatment time of BMA/AM/AA copolymer, the rearrangement reaction between molecular chains produces a six-membered imide ring. After cross-linking and solidification, PMI foam is obtained. The characteristic absorption peaks are in good agreement with the literature values. After heat treatment for 5 h, a dense closed cell foam with a pore diameter of 100-200 μm is obtained, which has good mechanical properties, compressive strength of 8.160 MPa and tensile strength of 12.95 MPa. The glass transition temperature (Tg) of the foam is 255℃, the thermal decomposition temperature Td10 is as high as 280℃ when the thermal mass loss is 10%, and the foam still retains more than 80% at 345℃, and the thermal conductivity is 0.05424 W/(m·K). It is indicated that the foam with excellent high temperature resistance and thermal insulation properties is obtained after heat treatment of the copolymer for 5 h.

Sipan-80, Tween-80 and sodium lauryl sulfate were used to synthesize the compound emulsifier with different formulations, and SiO2 as the carrier, hexadecanol-palmitic acid-lauric acid as a phase change material,a series of phase change and humidity controlling composites were made by sol-gel method. Effects of different compound emulsifier formulations on particle size distribution, microstructure, composition structure, thermal properties and humidity properties were studied by LPSA, SEM, FTIR, DSC and DVS, the influence mechanism of compound emulsifier on thermal properties and humidity properties of phase change and humidity controlling composites was analyzed. The results show that with Sipan-80, Tween-80 and sodium lauryl sulfate as compound emulsifier, phase change and humidity controlling composites with good thermal properties and humidity properties were prepared, such as phase change material with mass fraction of 70.34% to 74.00%, and the moisture content with relative humidity between 40% and 60% is 0.0361-0.0390g/g. With Sipan-80, Tween-80 and sodium lauryl sulfate as compound emulsifier can effectively improve the particle size distribution and uniformity coefficient of phase change and humidity controlling composites, and improve the dispersion of phase change and humidity controlling composites.

Copyright of China Plastics / Zhongguo Suliao is the property of Journal Office of CHINA PLASTICS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Cotton Textile Technology is the property of Cotton Textile Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

N,N’-di(4-propargyloxyphenyl) phosphoramide (DPPPA) was successfully synthesized by nucleophilic substitution of 4-propargyloxy aniline and phenylphosphonyl dichloride. The structure of DPPPA was characterized by nuclear magnetic resonance (NMR) and Fourier transformation infrared (FT-IR) analyses. DPPPA was used to mix with bisphenol A of dicyanate ester (BADCy) and bisphenol E of dicyanate ester (BEDCy) in solution. The DPPPA modified cyanate esters (BADCy/DPPPA and BEDCy/DPPPA) were obtained after the solvent was evaporated under vacuum. The thermal properties, limited oxygen index (LOI) and mechanical properties of the modified cyanate esters were studied. The results show that the residual yield at 800 ℃ in air of the cured BADCy/DPPPA and cured BEDCy/DPPPA increase from 0 to 33% and 26% in comparison with the cured neat cyanate esters, and the LOI of the cured modified cyanate esters reach 39.7% and 35.4%, but the glass transition temperatures of the cured modified cyanate esters decrease by 19 ℃ and 24 ℃, respectively. The flexural and tensile strength of the cured BADCy/DPPPA are 123 MPa and 45 MPa, which are higher than that of the cured BEDCy/DPPPA. The impact strength of the cured BADCy/DPPPA and BEDCy/DPPPA are 11 kJ/m² and 14 kJ/m², respectively. The water absorption of the cured neat cyanate esters decreases with blended with DPPPA. [ABSTRACT FROM AUTHOR]

Polymethacrylimide foams were prepared by free radical bulk polymerization with butyl methacrylate (BMA), acrylamide (AM) as the reactive monomer, acrylic acid (AA) as the third monomer and crosslinker at different heat treatment time. The structure and properties were characterized by FTIR, SEM, TGA and DSC. The results show that with the increase of heat treatment time of BMA/AM/AA copolymer, the rearrangement reaction between molecular chains produces a six-membered imide ring. After cross-linking and solidification, PMI foam is obtained. The characteristic absorption peaks are in good agreement with the literature values. After heat treatment for 5 h, a dense closed cell foam with a pore diameter of 100-200 μm is obtained, which has good mechanical properties, compressive strength of 8.160 MPa and tensile strength of 12.95 MPa. The glass transition temperature (Tg) of the foam is 255℃, the thermal decomposition temperature Td10 is as high as 280℃ when the thermal mass loss is 10%, and the foam still retains more than 80% at 345℃, and the thermal conductivity is 0.05424 W/(m·K). It is indicated that the foam with excellent high temperature resistance and thermal insulation properties is obtained after heat treatment of the copolymer for 5 h.

The high-purity Lu2O3 and Er2O3 were used as raw materials, using independently design and manufacture automatic equal diameter EFG furnace, 7. 82% (atomic fraction) Er∶Lu2O3 single crystal of ϕ25 mm ×20 mm was grown by the EFG method, and the segregation coefficient is 0. 92. Annealing conditions were explored. XRD result is a pure phase, and the XRF result proves that the impurity content is low. The absorption cross-sections around 972 nm and 1 535 nm are calculated using absorption spectra to be 3. 24 ×10-21 cm² and 8. 43 ×10-21 cm², and FWHM are 28. 22 nm and 27. 31 nm, respectively. The thermal property test results show that the thermal conductivity is 13. 28 W·m-1 ·K-1 at 30 ℃. The crystal surface micromorphology was characterized by SEM. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Explosives & Propellants is the property of Chinese Journal of Explosives & Propellants Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Silica aerogels are nanoporous materials with three-dimensional framework network structure. Silica aerogels have many unique properties such as high porosity, low density, low thermal conductivity and acoustical insulation properties. However, due to the poor mechanical performance of silica aerogels such as brittleness and high temperature instability, the large-scale commercial application of silica aerogels is limited. The thermodynamic properties of silica aerogels are related to their three-dimensional ligament network and pore structure . Exploring the relationship between microstructure evolution and macroscopic properties of silica aerogels is essential for improving their thermodynamic properties. Molecular dynamics ( MD) simulations are an appropriate tool for the study of mechanical properties from the atomistic level. Based on the accurate potential, MD simulations have correctly predicted the power law that relates thermal conductivity and density . MD simulations also analyze aerogel structure from the atomistic level and predict their thermodynamic performance . The interatomic potential, pore structure generation, structural characterization, mechanical properties and thermal conductivity of the silica aerogels from the aspect of MD simulations are summarized. This work contributes to explaining the relationship between the structure and properties of silica aerogels from the atomistic level, which can provide a theoretical guidance for designing silica aerogels in terms of composition and structure. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Explosives & Propellants is the property of Chinese Journal of Explosives & Propellants Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The recycled polypropylene (RPP) and ethylene-octene copolymer (POE) were used as the main raw materials. The RPP/POE blends were prepared by melt blending method. The mechanical properties and thermal properties of RPP/POE blends as well as the effect of compatibilizers on the mechanical properties were studied. The results showed that with the increase of POE addition, the tensile strength and impact strength of RPP/POE blends increased at first and then decreased, elongation at break tended to increase first and then stabilize, but the flexural strength decreased gradually. When the addition of POE was 5%, the tensile strength of the blend reached its maximum 16.7 MPa. When the addition of POE exceeded 20%, the elongation at break reached 400%, the impact strength increased to 5 times of that of RPP, and the flexural decreased to 50% that of RPP. Furthermore, the Vicat softening temperature of the blends decreased with an increase of the POE addition, and the introduction of POE had a little influence on the crystal structure of RPP, but had a baffling effect on the crystallization of RPP. Moreover, compared with PP-g-MAH, compatibilizer POE-g-MAH was more suitable for improving the strength and toughness of RPP/POE blends. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Explosives & Propellants is the property of Chinese Journal of Explosives & Propellants Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Effect of low-melting-point curing agent (MOEA) on property of epoxy resin was studied. The properties of epoxy resin (MOEA40) with MOEA as the curing agent were characterized and compared with the epoxy resin (DDM30) with 4, 4'-diaminodiphenyl methane (DDM) as the curing agent. The viscosity-temperature property, curing behavior, mechanical properties and thermal properties were characterized by rotational rheometer, differential scanning calorimetry (DSC), universal material testing machine, dynamic thermomechanical analyzer (DMA) and thermal gravimetric analyzer (TGA), respectively. The results show that MOEA40 has better viscosity-temperature property than that of DDM30. MOEA shows low viscosity (0.2-3.5Pa·s) in the temperature range of 60-140℃. MOEA40 and DDM30 are cured with the same curing progressing. Cured MOEA40 shows outstanding mechanical properties with bending strength about 147MPa and tensile strength about 89 MPa, which are 9.7% and 11.2% higher than that of cured DDM30 (bending strength 134MPa, tensile strength 80MPa). In addition, cured MOEA40 shows higher glass transition temperature (168℃) and higher thermal stability with 5% mass loss temperature about 367℃ in nitrogen atmosphere.