Structural,mechanical, thermal,and electrical properties of carbon black reinforced polyester resin composites

Carbon black (CB) reinforced polyester resin (PR) composites (CPC) have been fabricated from mechanical mixtures of liquid PR and CB powder having 0–50 wt% CB contents and cured with 1% of methyl ethyl ketone peroxide at room temperature under a pressure of 50 MPa. The samples have been examined by the Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD) technique, scanning electron microscopy (SEM), mechanical test, micromechanical test, differential thermal analysis (DTA), and thermogravimetric analysis (TGA) and electrical test. FTIR spectra confirm the physical and chemical bond formations between CB and PR. XRD shows a very partial crystalline structure in cured PR and hexagonal structure in CB particles. SEM exhibits a clear dispersion of CB particles in PR matrix at lower loading and aggregates at higher loading. With the increase of fillers, while the tensile and flexural strengths of CPCs decrease, the Young's and tangent modulii increase by 80 and 100%, respectively. These increments are found consistent with the theoretical values. The degree of physical crosslinking between CB and PR as well as the aspect ratio of CB in CPCs are found to increase with the increase of filler. A remarkable increase in microhardness of about 61% at 50 wt% CB content is observed. The TGA represents that the thermal degradation temperature for pure PR is 373°C and that for CPC is 393°C. The dielectric constant of CPCs decreases with increasing frequency, whereas the ac‐ and dc‐ conductivities of CPC are found to increase with CB content. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40421.     

Ultraviolet‐curing behavior and mechanical properties of a polyester acrylate resin

Ultraviolet (UV) curing technology has been widely used in many applications because it has several distinct advantages compared to solvent‐based processes or thermal‐curing technology. The effects of photoinitiator types and their contents as well as reactive diluent types and their contents on the UV‐curing behavior and mechanical properties of a UV‐curable polyester acrylate resin were investigated in this study. Three photoinitiators, Irgacure 184, Darocur 1173, and benzophenone, were used in this study. Hexanediol diacrylate, tripropylene glycol diacrylate, and trimethylol propane triacrylate were used as reactive diluents to modify the properties of the acrylate resin. The change of chemical structure during UV curing was monitored by FTIR. A universal testing machine was used to measure the tensile properties of various UV‐cured acrylate films of different compositions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3921–3928, 2004     

Effect of water aging on the mechanical properties of flax fiber/bio-based resin composites

Present work investigates the effect of hydrothermal aging of flax fiber-reinforced bio-based epoxy resin laminates on the mechanical and thermomechanical properties of the composites. Three different types of bio-based resins were used. Plates reinforced with eight layers plain weave flax fibers of 150 g/m², manufactured using Resin Transfer Molding (RTM), compression molding or autoclave technique depends on type of the resin. One dimensional Fickian behavior shows a good fitting to the experimental data derived from weight measurements. The water uptake at the equilibrium state in the case of 60 °C temperature was slightly greater than that at 40 °C. The mechanical properties after hydrothermal aging show a significant reduction and do not return to their initial values even after the drying process. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48787.     

Morphology development and mechanical properties of unsaturated polyester resin containing nanodiamonds

Unsaturated polyester/styrene (UP ) resin was filled with nanodiamonds (NDs ) containing carboxyl and methacrylate functionalities using mechanical mixing. Field emission SEM exhibited a uniform dispersion of tightly bound aggregates of nanosized spherical NDs with good interfacial interaction. Rheological measurements exhibited a step increment in the shear viscosity of a UP /ND suspension at 0.6 wt% ND resembling a percolation state at this loading. Shear viscosity data supported by dynamic mechanical analysis results suggested the development of effective ND particles in which ND aggregates were covered by only polyester macromolecules. Accordingly, the morphology of UP /ND composites approached a quasi‐percolation state at 0.6 wt% in which effective ND particles were connected thoroughly, instead of direct ND ?ND contact, forming a co‐continuous polyester phase covering the ND particles. Based on such morphology, DSC and Fourier transform infrared analysis suggested the development of heterogeneous microgels in cured UP resin containing NDs which in turn governed the overall mechanical properties of the composites. © 2017 Society of Chemical Industry     

二茂铁甲酸封端不饱和聚酯的固化及热性能研究

以乙二醇、反丁烯二酸为原料合成的不饱和聚酯作为主链,二茂铁甲酸(FCA)作为封端剂,合成了含二茂铁基的不饱和聚酯(RFc),采用红外光谱对产物结构进行了表征。采用DSC及TGA研究了不同二茂铁甲酸含量对不饱和聚酯树脂固化性能和热稳定性的影响。结果表明,随着二茂铁甲酸含量的增加,RFc树脂固化反应活性减弱,热稳定性下降。其最高放热峰温度在171～173℃,且具有比较宽的加工温度范围(152～195℃),符合模塑料固化工艺要求。树脂的耐热性较好,初始热分解温度约为340℃,N2气氛下600℃残炭率可达19.76%。     

SiC颗粒增强不饱和聚酯树脂复合材料的力学性能

采用万能试验机和硬度计测试研究了SiC颗粒含量和粒径对不饱和聚酯树脂基复合材料力学性能的影响,通过扫描电子显微镜观察了拉伸试样的端口形貌。结果表明,填充的SiC质量分数为10%时,其不饱和聚酯树脂复合材料拉伸强度达到最大,8000目、1000目SiC填充体系拉伸强度分别为53.2MPa,44.8MPa,较纯树脂体系提高68.1%,41.5%。当SiC质量分数为30%时,SiC填充体系的弹性模量较纯树脂体系提高25.8%以上,硬度提高2.3%以上,SiC颗粒尺寸对复合材料的弹性模量和硬度影响不大。SiC/不饱和聚酯树脂复合材料的断裂属脆性断裂。     

高低温老化对碳纤维复合材料芯棒结构性能的影响

采用拉挤工艺制备了碳纤维增强环氧树脂基复合材料芯棒,并对其进行高低温人工加速老化试验,以及对老化前后碳纤维复合材料芯棒的横截面、外观颜色和密度进行了测试和分析。结果表明,高低温老化使芯棒颜色加深,主要对芯棒的外层产生一定的影响,内部结构没有明显变化;老化后芯棒的密度比老化前减小约2.5%,并且不同老化周期对芯棒的密度基本不变。     

Effect of thermal-oxidative aging on mechanical,chemical, and thermal properties of recycled polyamide 66

This article addresses the effect of thermal aging on unreinforced and glass-reinforced recycled polyamide 66. As an accelerated test, injection-molded test bars were aged at 110, 140, and 170°C for up to 4000 h in air to simulate service life. FTIR spectroscopy demonstrated that the oxidative degradation primarily occurred between the surface and a depth of 0.5 mm. Furthermore, the degradation in the surface region was more pronounced with recycled as well as unstabilized materials. Reprocessing resulted in a faster increase of carbonyl groups, a decrease in melting peak temperature, and elongation at break during subsequent aging. Because of process-induced fiber shortening, however, the elongation at break of recycled reinforced samples was always at least as high as that of virgin samples for up to 4000 h of aging at 140°C. The decrease in melting peak temperature as determined by differential scanning calorimetry (DSC) indicated that the surface or boundary regions of the crystallites in the material are affected by aging. The loss in elongation at break for the reinforced material was shown to correlate with the reduction in melting peak temperature of material taken from the surface region of aged samples. The contribution of the degraded surface region to the properties was studied by removal of surface layers prior to testing. The degradation in the surface region was the sole cause, even of glass fiber-reinforced polyamide, for the embrittlement of aged samples. Furthermore, aging-induced changes in tensile strength and modulus were independent of the removal of the surface region, indicating that these properties are controlled by changes occurring in the bulk of the material. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1619–1630, 1997     

环氧树脂含量对氰酸酯热学性能的影响研究

采用示差扫描量热法(DSC)和热失重分析法(TGA)研究了环氧树脂含量对氰酸酯树脂固化反应特性、热稳定性以及热膨胀系数的影响。结果表明,环氧树脂的加入可有效降低改性体系的固化反应活化能,同时体系的热稳定性和尺寸稳定性有不同程度的削弱。当环氧树脂质量分数达到20%时,改性体系的表观活化能为65.4 kJ/mol,耐热温度指数为174℃,较纯氰酸酯树脂分别降低了25.8%和21.4%。当环氧树脂质量分数达到50%时,改性体系的热膨胀系数为65.3 922×10-6/℃(25～150℃),较纯氰酸酯树脂提高了8.13%。     

聚砜改性环氧树脂复合材料热老化性能研究

以聚砜(PSF)改性环氧树脂(EP)为基体树脂,玻璃纤维为增强材料,采用高温模压成型法制备出PSF改性EP/玻璃纤维复合材料。结果表明:PSF能有效提高EP基体的热稳定性能;经200℃热老化72 h后,PSF改性EP/玻璃纤维复合材料的热失重率<1%,其冲击强度和弯曲强度呈先升后降态势,电绝缘性能仍然较好(其体积电阻率和表面电阻率的数量级仍保持在1012左右);该复合材料在高温绝缘场合中具有良好的应用前景。     

Effect of pine resin derivatives on the structural,thermal, and mechanical properties of Mater-Bi type bioplastic

The effect of three additives derived from pine resin, namely, gum rosin (GR) and two pentaerythritol ester of GR, Lurefor (LF) and Unik Tack (UT), in 5, 10, and 15 wt %, on the properties of Mater-Bi, based on plasticized starch, poly(butylene adipate-co-terephthalate), and poly(ε-caprolactone) (PCL), obtained by injection molding processes, was studied. The mechanical, microstructural, and thermal properties were evaluated. LF had a cohesive behavior with the components of Mater-Bi, increasing the toughness of the material up to 250% accompanied by an increase of tensile modulus and tensile strength. UT had an intermediate behavior, conferring cohesive and plasticizing effects, allowing an increase of 105% in impact resistance. GR had a more marked plasticizing effect. This allows processing temperatures of about 50 °C lower than those used for neat Mater-Bi. In addition, an increase of the elongation at break, toughness, and impact resistance in 370, 480, and 250%, respectively, was achieved. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48236.     

Environmental aging effects on thermal and mechanical properties of electrically conductive adhesives

This article investigates environmental aging effects on thermal and mechanical properties of three model electrically conductive adhesives (ECAs). A combination of several experimental techniques including thermogravimetric analysis (TGA), water uptake measurements, dynamic mechanical analysis (DMA), and stress-strain dogbone testing has been utilized throughout this study. Samples were aged at 85°C and 100% RH for periods of up to 50 days, and some of the samples were dried at 150°C after aging. Results obtained on aged samples with and without drying suggest that the conductive adhesives may have experienced both reversible and irreversible effects during environmental aging. Both plasticization, which is reversible, and further crosslinking and thermal degradation, which are irreversible, are indicated upon exposure of ECAs to the hot/wet environment.     

Influence of tragacanth resin on the thermal and mechanical properties of fly ash-cement composites

This study was aimed to search the possibility of usage of the thermal power plants fly ashes, cement and tragacanth composites in concrete or plaster by investigating their thermal insulation characteristics. The fly ash used in the experiments is supplied from Af?in Elbistan Thermal Power Station. Portland cement (KPC 325) with resin is used as binding and 24 specimens are prepared depending on the percentage of fly ash and tragacanth. In all fly ash, tragacanth and binding mixture, the weight percentages of fly ash are taken as 0, 10, 20, 30, 40 and 50%. The amount of the resin in the mixture is 0.5, 1 and 1.5% of the weight of the total cement and fly ash.

24 samples were prepared and tested to find out the effects of resin on thermal and mechanical properties of fly ash and cement composites. Whereas fly ash percentage increased from 0% to 50%, i) thermal conductivity and compressive strength decreased 19.37–28.62% and 7.66–16.55% respectively as the porosities of the samples increased 18.91–28.62% with the effect of artificial pores generated by 1.5% resin other than the pores generated by fly ash. ii) the new produced samples can be used as partition walls, floorings, ceiling concretes, briquettes or bricks and plaster.     

The effect of reactive monomers and functional polymers on the mechanical properties of an unsaturated polyester resin

A general-purpose unsaturated polyester resin with 2:1 mol ratio of styrene to polyester unsaturation was modified with three vinyl monomers and two hydroxyl terminated polybutadienes. Tensile, flexural, and puncture impact properties were examined. The three acrylate monomers were tetraethylene glycol dimethylacrylate, 1,3 butylene glycol dimethacrylate, and trimethylpropane trimethylacrylate with weight percents of 2.5, 5, 15, and 30. Two hydroxyl terminated polybutadienes with slightly different contents of hydroxyl functionality were also employed in the weight percents of 2.5, 5.0, and 10.0. Results showed that an increase in the number of crosslinks and crosslink density resulted in a deterioration in the mechanical properties. The addition of an immiscible polybutadiene polymer to the polyester resin also showed a decrease in the mechanical performance of the resulting thermoset materials.     

Change in the mechanical properties of para-aramid fibres in thermal aging

The change in the mechanical properties of high-strength, high-modulus carbocyclic and heterocyclic para-aramids exposed to high (250, 275, 300°C) temperatures for up to 100 h was investigated. It was found that the change in the strength characteristics and elongation at break after prolonged thermal effects is diminishing in character. A small increase in the elongation, probably caused by predominance of the effect of structural transformations over degradation processes, was only observed in the fibres based on CpPABI in the initial period at 250 and 275°C. The data on the change in the strength and elongation at break as a function of the duration of the thermal effect are described by exponential dependences: second order for the elongation at break of Rusar and Armos fibres at 250 and 275°C and first-order in the other cases. The values of the coefficients in these dependences were found. The data obtained and curves approximating them describe the change in the strength and elongation at break of para-aramid fibres in the time range of up to 100 h and can be used to approximately predict the change in them over a longer period. The results of the study of the effect of high temperatures on the mechanical properties of high-strength, high-modulus para-aramid fibres can be used to determine the temperature boundaries of use of articles made from them. It follows from the data obtained that these articles can be used for a long time at 250 and even 275°C and briefly up to 300°C. __________ Translated from Khimicheskie Volokna, No. 5, pp. 44–49, September–October, 2006.     

Impact of synergism of LDH with PNCC on the thermal and mechanical properties of polyester nanocomposites

ABSTRACT

Present study investigates, the synergistic effect of Precipitated Nano Calcium Carbonate with Layered Double Hydroxides (LDHs) on thermal and mechanical properties of unsaturated polyester resin. A polyester-LDH-PNCC nanocomposite was prepared using “slurry-compounding” method. Meanwhile, PNCC was prepared by in-situ deposition (matrix-mediated growth and controlled) technique, crystal dimension of PNCC was estimated by using Transmission Electron Microscope (TEM). Surface morphology and mechanical properties were studied by using Field Emission Scanning Electron Microscopy (FESEM) and Universal Tensile Machine (UTM) respectively. Wide angle X-ray diffraction (WAXD) study revealed the formation of polyester nanocomposites. The nanocomposites showed better thermal and mechanical properties than that of the unmodified polyester resin, thus, synergism of LDH-PNCC influenced thermal and mechanical properties of polyester nanocomposites.     

热介质老化对HNBR力学性能的影响

采用加速老化实验方法研究了热介质对氢化丁腈橡胶（HNBR）材料力学性能的影响,获得了热空气、ASTM 1#标准油和ASTM 3#标准油中老化温度及老化时间对HNBR材料力学性能的影响规律。结果表明,HNBR材料具有良好的力学性能和耐油性能。     

Effect of physical aging and thermal stress on the behavior of polyester/TGIC powder coatings

Physical aging, thermal stress, dynamic mechanical characteristics and thermal expansion of powder coatings from model terephthalic acid (TPA) and isophthalic acid (IPA)-based polyesters (PEs) cross-linked with triglycidyl isocyanurate (TGIC) were studied. Enthalpy relaxation and maximum compressive thermal stress were the properties used to follow the physical aging. The better mechanical properties of TPA-based PE/TGIC powder coatings seem to be due to a combined effect of several properties, i.e., cross-link density (ν_e), thermal expansion coefficient (_F^T) and glass transition temperature (T_g). The higher the values of ν_e, (_F^T) and T_g, the tighter is the coating network, the greater is the coating ability to expand thermally and the slower the physical aging process, respectively, all factors favoring the TPA polyester-based powder coatings.