Modification of Epoxy Resin Using Liquid Natural Rubber

2006 ◽  
Vol 517 ◽  
pp. 272-274 ◽  
Author(s):  
Ismail Zainol ◽  
Mohamad Ibrahim Ahmad ◽  
Fadzil Ayad Zakaria ◽  
Anita Ramli ◽  
Haslan Fadli Ahmad Marzuki ◽  
...  

The cure process and the mechanical properties of liquid polymethylmethacrylate grafted natural rubber (LMG30) modified epoxy have been studied. Addition of LMG30 significantly increased the fracture toughness and the impact strength of the epoxy resin. The fracture toughness increased up to 22 fold (17.3 MNm-3/2) when modified with 5 phr LMG30. The glass transition temperature however, decreases as the rubber content increases. The SEM analysis shows uniform dispersion of rubber particles within the epoxy matrix with average particle size between 0.4 to 0.8 0m in diameter.

Author(s):  
И.В. Бачериков ◽  
Б.М. Локштанов

При проектировании открытых и закрытых хранилищ измельченных сыпучих материалов древесных материалов, таких как щепа и опилки, большое значение имеет угол естественного откоса (статический и динамический) этих материалов. В технической литературе приводятся противоречивые сведения о величине этих углов, что приводит к ошибкам при проектировании складов. В справочных данных не учитываются условия, в которых эксплуатируются емкости для хранения сыпучих материалов, свойства и состояние этих сыпучих материалов. В свою очередь, ошибки при проектировании приводят к проблемам (зависание, сводообразование, «затопление» и т. д.) и авариям при эксплуатации бункеров и силосов на производстве. В статье представлены сведения, посвященные влиянию влажности и температуры на угол естественного откоса сыпучих материалов. На основании лабораторных и натурных экспериментов, проведенных с помощью специально разработанных методик и установок, была скорректирована формула для определения углов естественного откоса (статического и динамического) для измельченных древесных материалов в зависимости от их фракционного и породного состава, влажности (абсолютной и относительной) и температуры. При помощи скорректированной формулы можно определить угол естественного откоса древесных сыпучих материалов со среднегеометрическим размером частицы от 0,5 мм до 15 мм (от древесной пыли до технологической щепы) в различных производственных условиях. Статья может быть полезна проектировщикам при расчете угла наклона граней выпускающей воронки бункеров и силосов предприятий лесной отрасли и целлюлозо-бумажной промышленности. In the design of open and closed storage warehouses chopped wood materials for bulk materials such as wood chips and sawdust, great importance has an angle of repose (static and dynamic) of these materials. In the technical literature are conflicting reports about the magnitude of these angles, which leads to errors in the design of warehouses. In the referencesdoes not take into account the conditions under which operated capacities for storage of bulk materials, and properties and condition of the bulk material. The design errors lead to problems (hanging, arching, «flooding», etc.) and accidents in the operation of hoppers and silos at the mills. The article provides information on the impact of humidity and temperature on the angle of repose of granular materials. On the basis of laboratory and field experiments, conducted with the help of specially developed techniques and facilities has been adjusted formula for determining the angle of repose (static and dynamic) for the shredded wood materials depending on their fractional and species composition, humidity (absolute and relative) and temperature. It is possible, by using the corrected formula, to determine the angle of repose of loose wood materials with average particle size of from 0.5 mm to 15 mm (wood dust to pulpchips) in various operating conditions. The article can be helpful to designers in the calculation of the angle of inclination of the funnel faces produces bunkers and silos forest industries and pulp and paper industry.


2007 ◽  
Vol 121-123 ◽  
pp. 1451-1454
Author(s):  
Jian Feng Chen ◽  
Guo Quan Wang ◽  
Xiao Fei Zeng ◽  
Hong Ying Zhao

Nanocomposites of nanosized-CaCO3/polypropylene-ethylene copolymer (PPE) and nanosized CaCO3/ PPE/ styrene-butadiene-styrene (SBS) were prepared by using two-roll mill and single screw extruder. The average particle size of nanosized CaCO3 was determined to be about 30 nm. By adding nanosized CaCO3 into PPE matrix, the toughness of the matrix improves significantly. At nanosized CaCO3 content of 12 phr (parts per hundred PPE resin by weight), the impact strength of CaCO3/PPE at room temperature reaches 61.6 KJ/m2, which is 3.02 times that of unfilled PPE matrix. In addition, the synergistic toughening effect of nanosized CaCO3 and SBS particles on PPE matrix was investigated.


2022 ◽  
Vol 8 ◽  
Author(s):  
Ao Li ◽  
Aixia Zhu ◽  
Di Kong ◽  
Chunwei Wang ◽  
Shiping Liu ◽  
...  

For improving solubility and bioaccessibility of phytosterols (PS), phytosterol nanoparticles (PNPs) were prepared by emulsification–evaporation combined high-pressure homogenization method. The organic phase was formed with the dissolved PS and soybean lecithin (SL) in anhydrous ethanol, then mixed with soy protein isolate (SPI) solution, and homogenized into nanoparticles, followed by the evaporation of ethanol. The optimum fabrication conditions were determined as PS (1%, w/v): SL of 1:4, SPI content of 0.75% (w/v), and ethanol volume of 16 ml. PNPs were characterized to have average particle size 93.35 nm, polydispersity index (PDI) 0.179, zeta potential −29.3 mV, and encapsulation efficiency (EE) 97.3%. The impact of temperature, pH, and ionic strength on the stability of fabricated PNPs was determined. After 3-h in vitro digestion, the bioaccessibility of PS in nanoparticles reached 70.8%, significantly higher than the 18.2% of raw PS. Upon freeze-drying, the particle size of PNPs increased to 199.1 nm, resulting in a bimodal distribution. The solubility of PS in water could reach up to 2.122 mg/ml, ~155 times higher than that of raw PS. Therefore, this study contributes to the development of functional PS-food ingredients.


2019 ◽  
Vol 13 (3) ◽  
pp. 234-240
Author(s):  
Elnaz Moslehifard ◽  
Mahmood Robati Anaraki ◽  
Saeed Shirkavand

Background. The current study evaluated the compressive, flexural and impact strengths of heat-cured acrylic resins reinforced by TiO2 nanoparticles (NPs). Methods. TiO2 NPs were provided and characterized using scanning electron microscopy (SEM) to determine their morphology and crystalline structure. For three mechanical tests, 12 acrylic resin groups (n=9), totaling 108 specimens, were prepared using a special mold for each test, with TiO2 nanoparticle contents of 0, 0.5, 1 or 2 wt% in different groups. After curing, the compressive, flexural and impact strengths of the specimens were examined according to ISO 1567. Results. In the SEM and XRD study of TiO2 NPs, anatase was identified as the major crystalline phase followed by rutile (average particle size: 20.4 nm). SEM images showed that the nanocomposite with 1 wt% NPs had a more homogenized blend. 1 wt% TiO2 nanocomposite exhibited a higher, but non-significant, impact strength compared to the controls. ANOVA showed significant differences in the impact and flexural strengths between nanocomposites with various contents of TiO2 NPs. Conclusion. The nanocomposite with 1 wt% TiO2 NPs exhibited fewer micro-pores and micro-cracks in the SEM cross-sections. A non-significant increase was also observed in the impact strength with TiO2 NPs at 1 wt%. Further increase in TiO2 NPs decreased both the impact and flexural strengths. The compressive strength of the heat-cured acrylic resin was not affected by the incorporation of NPs.


2013 ◽  
Vol 66 (5) ◽  
pp. 564 ◽  
Author(s):  
Mingmei Zhang ◽  
Qian Sun ◽  
Zaoxue Yan ◽  
Junjie Jing ◽  
Wei Wei ◽  
...  

Well dispersed Pd@Ni bimetallic nanoparticles on multi-walled carbon nanotubes (Pd@Ni/MWCNT) are prepared and used as catalysts for the oxidation of benzyl alcohol. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy analysis, and X-ray diffraction were performed to characterise the synthesised catalyst. The results show a uniform dispersion of Pd@Ni nanoparticles on MWCNT with an average particle size of 4.0 nm. The as synthesised catalyst was applied to the oxidation of benzyl alcohol. A 99 % conversion of benzyl alcohol and a 98 % selectivity of benzaldehyde were achieved by using the Pd@Ni/MWCNT (Pd: 0.2 mmol) catalyst with water as a solvent and H2O2 as oxidant at 80°C. The catalytic activity of Pd@Ni/MWCNT towards benzyl alcohol is higher than that of a Pd/MWCNT catalyst at the same Pd loadings. The catalyst can be easily separated due to its magnetic properties.


2021 ◽  
pp. 37-43
Author(s):  
S.S. Samotugin ◽  
V.I. Lavrinenko ◽  
Yu.S. Samotugina ◽  
O.A. Khristenko ◽  
O.N. Shicheva ◽  
...  

The regularities of the structure formation and changes in the fracture toughness parameters of the Kh12M steel are studied for various technological variants of plasma surface modification. The possibility for the formation of nanocrystalline martensite-carbide structure with average particle size of 50...150 nm in the surface volumes at the cutting edge of cold-working tool is shown.


Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1522
Author(s):  
Ming Zhang ◽  
Mingqing Chen ◽  
Zhongbin Ni

We synthesized PPG-terminated tetra-carbamates as a new toughening additive for epoxy thermosets through facile addition reaction of hexamethylene diisocyanate (HDI) with poly(tetra-methylene glycols) (PTMG) and poly(propylene glycols) (PPG). The effects of prepared tetra-carbamates on the rheological behavior of neat epoxy resin were studied along with the various cured properties of their modified epoxy systems. Four carbamate groups (–NHCOO–) endow the prepared additives not only with good intramolecular interactions, but also with optimal intermolecular interactions with epoxy polymers. This results in the suitable miscibility of the additives with the epoxy matrix for the formation of the typical biphasic structure of microparticles dispersed in the epoxy matrix via polymerization-induced microphase separation. The impact strength and critical stress concentration factor (KIC) of cured modified epoxy systems with the additives are significantly higher than those of unmodified epoxy systems, without sacrificing the processability (Tg) and flexural strength. The toughening mechanism is understood as a synergism combination among the phase separation mechanism, the in situ homogeneous toughening mechanism, and the particle cavitation mechanism.


2013 ◽  
Vol 401-403 ◽  
pp. 713-716
Author(s):  
Cheng Fang ◽  
Dong Bo Guan ◽  
Wei Guo Yao ◽  
Shou Jun Wang ◽  
Hui An

The epoxy resin was modified with the mixture of α,ω-dihydroxy poly-(3,3,3-trifluoropropyl) siloxane (PTFPMS), KH560 and stannous octoate. KH560 can react with PTFPMS and also epoxy resin curing agent. The two reactions were characterized by FI-IR. The modified epoxy resin was characterized by FI-IR. The result showed that fluorine-containing silicone had been successfully introduced into the epoxy system. The mechanical and thermal properties of the modified epoxy resin were analyzed. The results showed that with the increase of PTFPMS the impact strength of epoxy resin increased, hardness and bending strength correspondingly reduced, slight decrease in the glass transition temperature.


2015 ◽  
Vol 744-746 ◽  
pp. 1463-1466
Author(s):  
Xi Wang

This paper presents the synthesis of a new type of flexible epoxy curing agent and an approach to improve the toughness of epoxy resin by curing without reducing the strength and modulus of the resin-cured material. The results show that the degree of toughness reaches maximum values when the flexible curing agent is applied at weight percentages (wt.%) between 10% and 15%. When the amount of flexible curing agent added to epoxy resin weight is 10wt.%, the impact toughness and fracture toughness increases by 33.3% and 96.3%, respectively, compared with the pure epoxy resin. When the amount of flexible curing agent added to epoxy is 10wt.%, the resulting impact thoughness of the material is 19.5 kJ•m-2 at-50°C, the impact toughness of pure epoxy resin is only 7.96 kJ•m-2.


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