Crystallization behavior of polypropylene/ethylene butene copolymer blends

One polypropylene (PP) was mixed with two ethylene butene copolymers (EBM). EBM1 had 12.5 mol % of butene and was immiscible with the PP. EBM2 had 51.6 mol % of butene and was miscible with the PP. The dispersed PP in EBM1 showed fractionalized crystallization behavior with a crystallization temperature at around 45°C and a much slower isothermal crystallization rate comparing to the neat PP. The PP did not exhibit fractionalized crystallization behavior in EBM2. EBM1 did not decrease both the crystallization and melting temperatures of the continuous PP. However, EBM2 could decrease both the two temperatures. It was found that EBM2 could largely suppress the epitaxial lamellar branching of the PP. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Phase morphology and compatibilization mechanism in ternary polymer blend systems of polyethylene terephthalate,polyolefin rubber,and ionomer

The phase morphology and the mechanism of the compatibilization in ternary blends of PET/EBM (ethylene buten rubber)/ionomer (partially neutralized ethylene and methyl methacrylic acid copolymer, EMAA) are examined. Applying the repulsion idea in random copolymer, the ionomer was selected as an encapsulating agent to compatibilize PET/EBM blend. As anticipated, the ionomer can encapsulate EBM in PET matrix and effectively compatibilize PET and EBM. The results of droplet sandwich experiments verified that the actual driving force for the encapsulation is wettability. In addition, this wettablility was found to be realized by the contribution of the polar and nonpolar units in the ionomer: The polar units decrease the interfacial tension between PET and the ionomer, and the nonpolar units decrease that between EBM and the ionomer. The metal ions in the ionomer have little influence on the wettability, and consequently EMAA can encapsulate EBM even when unneutralized. The efficiency of the compatibilization, on the other hand, is not determined by the wettability only, and the metal ions play an important role. EMAA can effectively compatibilize EBM and PET only when neutralized. This compatibilization effectiveness of the ionomer is supposedly due to the strong interaction between PET and the metal ions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1567–1576, 2004     

Additive manufacturing of ZrB2–ZrSi2 ultra-high temperature ceramic composites using an electron beam melting process

Owing to their high melting points and ability to resist extreme thermal stresses, ultra-high temperature ceramics (UHTCs) are important materials for critical applications such as hypersonic flights, space re-entry vehicles, and rocket engines. Traditional manufacturing processes restrict the freedom to manufacture UHTCs with complex geometries due to the limitations of die and mold designs. Electron beam melting (EBM) is an established powder-bed layer-by-layer additive manufacturing (AM) process for metal parts. In this research, an effort was made to evaluate the feasibility of EBM for the AM fabrication of UHTC-based materials, and to investigate the microstructures of the fabricated materials under different processing conditions. A mathematical model was developed to simulate and optimize the processing parameters for the fabrication of ZrB₂-30 vol% ZrSi₂ UHTC using EBM. The simulation results were compared with experimental observations. For EBM fabrication of ZrB₂-30 vol% ZrSi₂ composites, the optimal processing parameters are beam power of 500 W with scanning speeds of 500, 750, and 1000 mm/s, and beam power of 1000 W with scanning speed of 1000 mm/s. This study demonstrates the potential for additive manufacturing of UHTCs with complex geometries by the EBM technique.     

An extended bottleneck model: Accounting for the metabolic turnover effect in microorganisms

The bottleneck model proposed by Powell¹ can describe the growth rate hysteresis effect, but fails to account for the stationary state of microbial cultures. It is modified to obtain an extended bottleneck model (EBM), which adequately represents the stationary state of microbial cultures. The basis for modification is the metabolic turnover of proteins in microorganisms. Under special conditions the EBM can be reduced to the Powell bottleneck model or the Monod model. The EBM yields improved predictions of the transient growth of E. coli in nitrogen limited cultures.     

Droplets diameter distribution using maximum entropy formulation combined with a new energy-based sub-model

The maximum entropy principle (MEP) is one of the first methods which have been used to predict droplet size and velocity distributions of liquid sprays. This method needs a mean droplets diameter as an input to predict the droplet size distribution. This paper presents a new sub-model based on the deterministic aspects of liquid atom-ization process independent of the experimental data to provide the mean droplets diameter for using in the maximum entropy formulation (MEF). For this purpose, a theoretical model based on the approach of energy conservation law entitled energy-based model (EBM) is presented. Based on this approach, atomization occurs due to the kinetic energy loss. Prediction of the combined model (MEF/EBM) is in good agreement with the avail-able experimental data. The energy-based model can be used as a fast and reliable enough model to obtain a good estimation of the mean droplets diameter of a spray and the combined model (MEF/EBM) can be used to wel predict the droplet size distribution at the primary breakup.     

Poly(Amide‐Imide)s Based on Amino‐Terminated Oligoimides

Abstract

An amino‐terminated oligoimide was prepared by the Michael addition reaction of ethylene bis‐maleimide (EBM) and 4,4′‐diamnio diphenyl‐sulfone (DDS) at an EBM:DDS molar ratio of 1:2. The poly(amide‐imide)s (PAI)s were prepared by condensation of this EBMDDS oligoimide with various aliphatic bisesters. The resultant PAIs were characterized by elemental analysis, IR spectral studies, and the number average molecular weight estimated by non‐aqueous conductometric titration and thermogravimetry. The curing reaction of an epoxy resin [a diglycidyl ether of bis‐phenol‐A (DGEBA)] with PAIs was monitored by differential scanning calorimetry (DSC). Glass‐ and carbon‐reinforced laminates of PAI‐epoxy resin were also prepared and characterized.     

Corrosion evaluation of Ti–6Al–4V manufactured by electron beam melting in Ringer’s physiological solution: an in vitro study of the passive film

Journal of Applied Electrochemistry - Electrochemical characteristics and semiconducting behavior of additively manufactured electron beam melted (EBM) and wrought (WR) Ti–6Al–4V...     

EBM气溶胶灭火剂产物的潮解研究

EBM气溶胶灭火剂是一种新型高效灭火剂,其灭火效率高于哈龙类灭火剂。燃烧反应产生的白色烟雾对火灾具有抑制作用。白色烟雾中含有固体颗粒物质,这些颗粒物降落形成的残留物潮解后对金属材料及线路板等有腐蚀性。对气溶胶灭火剂颗粒物潮解进行研究,研究结果表明:空气的相对湿度是影响气溶胶颗粒物潮解的主要因素。     

Addition of long-chain polyunsaturated fatty acids to formula for very low birth weight infants

Thirty-four premature infants who were appropriate for gestational age and weighing less than 1500 g at birth were fed “preemie” SMA-24 formula, “preemie” SMA-24 formula manufactured to contain C₂₀ and C₂₂ ω6 and ω3 fatty acids (LCPE-SMA), or expressed milk (EBM). Blood samples were drawn from a small arm vein during the first week of life and after 28 days of feeding. The fatty acid content of plasma phospholipids was determined. Infants fed SMA-24 had a high content of 18∶2ω6 in plasma phospholipids. Feeding LCPE-SMA normalized plasma phospholipid levels of C₂₀ and C₂₂ ω6 and ω3 fatty acids to be similar to levels of C₂₀ and C₂₂ ω6 and ω3 fatty acids found in infants fed EBM, and significantly higher than characteristic levels for infants fed SMA-24. Feeding LCPE-SMA or EBM results in a balanced incorporation of C₂₀ and C₂₂ ω6 and ω3 fatty acids into phospholipids derived from the liver or perhaps the small intestine. Based on a paper presented at the Symposium on Milk Lipids held at the 1990 AOCS Annual Meeting, Baltimore, MD, April 1990.     

温湿度对EBM气溶胶灭火剂吸湿的影响

EBM气溶胶灭火剂是一种新型高效灭火剂,其灭火效率高于哈龙类灭火剂.燃烧反应产生的白色烟雾对火灾具有抑制作用.白色烟雾中含有固体颗粒物质,这些颗粒物降落形成残留物湿后的残留物对金属材料及线路板等有腐蚀性.研究了温湿度对气溶胶灭火剂吸湿的影响.研究结果表明:空气的相对湿度是影响气溶胶颗粒物吸湿的主要因素.     

Intrinsic flame-retardant epoxy resin composites with benzoxazine: Effect of a catalyst and a low curing temperature

Three kinds of inherent flame-retardant epoxy resin (EP) composites with 20 wt % benzoxazine (BOZ) were prepared with different curing processes with 2-methyl-1H-imidazole (MI) as a catalyst or/and changes in the curing temperature. The effects of the curing process on the flame retardancy, thermal stability, mechanical properties, and curing behaviors were investigated. The composite with added MI cured at low temperature (EBM–LT) had the best properties. It possessed a 35.3% limiting oxygen index and achieved a UL 94 V-0 rating. Thermogravimetric analysis indicated that EBM–LT had the best thermal stability among the three kinds of EP composites with BOZ. The EP composites with BOZ mainly displayed a condensed-phase flame-retardant mechanism. The mechanical properties improvement was attributed to the formation of a heterogeneous network. Differential scanning calorimetry indicated that MI reacted with EP and catalyzed the homopolymerization of BOZ, and EP reacted with BOZ. Fourier transform infrared spectroscopy analysis indicated that curing at lower temperature caused the formation of more homopolymers of BOZ. The relationship of the curing process, network structure, and properties of EP composites with BOZ was established; this could help with the design of high-performance EP composites with BOZ. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47847.     

有机酸钾盐对气溶胶发生剂的消焰降温作用研究

研究了有机酸钾盐对于一种烟火型气溶胶发生剂 (EBM灭火剂 )的消焰降温作用 ,对比分析了不同有机酸钾盐在不同添加量时的改性效果     

Study,Mechanical Characterization and Mathematical Modeling of Compatible SEBS Blends for Industrial Applications in Orthopedics and Childcare

In this work, a system of compatible blends based on two commercial grades of a thermoplastic elastomer, styrene-ethylene/butylene-styrene (SEBS), with extreme Shore A hardness values (5 and 90), was studied in order to obtain a range of different performance blends for orthopedic and childcare applications, where usually liquid silicone rubber is used. Mechanical properties of different blends were obtained, and Equivalent Box Model (EBM) was used for the prediction of the mechanical behavior. The results show good agreement between the theoretical model and experimental data of new blends of SEBS.     

Oligoimide Containing 8-Hydroxyquinoline as a Pendent Group

New ethylenebismaleimide-diamine oligoimide-II (EBMDDMCMHQ) containing 8-hydroxyquinoline as a pendent group(s) was prepared using ethylenebismaleimide-diamine oligoimide-I (EBMDDM) and 5-chloromethyl-8-hydroxyquinoline hydrochloride (CMHQ) in the presence of base catalyst. Ethylenebismaleimide-diamine oligoimide-I (EBMDDM) was prepared by the Michael addition reaction of ethylenebismaleimide (EBM) and 4,4′-diaminodiphenyl methane (DDM). The resulting oligoimide-II (EBMDDMCMHQ) was characterized by spectral techniques. Polymeric metal chelates of oligoimide-II were prepared using transition metal ions and were duly characterized. Ion-exchange properties of oligoimide-II for Fe(III), Zn(II), Ni(II), and Cu(II) metal ions were also studied by batch-equilibration method. It has good metal ion uptake capacity at varying pH ranges.     

添加剂降低气溶胶发生剂火焰温度的研究

研究了两种添加剂对一种气溶胶发生剂（EBM灭火剂）的火焰温度的影响,发现这两种添加剂具有明显降低气溶胶发生剂燃烧火焰温度的作用,当两种添加剂同时使用时,改性样品具有更加优良的综合性能。     

Influence of firing conditions and production methods on fracture strength of titanium-based metal ceramic crowns

Objectives: This study evaluated the effect of argon atmosphere compared with vacuum during porcelain firing on the fracture strength of crowns made of porcelain and electron beam melted (EBM) Ti-6Al-4 V, cast commercially pure titanium or milled commercially pure titanium. Methods: Sixty crown copings of c. p. titanium, Ti-6Al-4 V alloy and porcelain were fabricated using three production techniques. The copings were fired either under vacuum or in an argon gas atmosphere. Specimens were subdivided into groups of cast c. p. titanium, milled c. p. titanium and EBM Ti-6Al-4 V which were further subdivided according to firing modes employing either vacuum or argon gas. The 60 specimens were subjected to cyclic preloading and thermocycling, and were then individually loaded until interface fractured. Differences between the group mean values were calculated using the one-way ANOVA and Tukey’s range test. Two fractured samples from each group were cut with a diamond blade and examined using SEM and EDS for visualization and chemical composition analysis of the fractured interface. Results: The highest mean fracture strength values, though not significant, were recorded for the groups fired in argon atmosphere, and the lowest mean fracture strength values were recorded for the groups fired in vacuum, with one exception. Comparing the two main groups of firing atmosphere, no significant difference could be documented. SEM and EDS analysis indicated clear differences in composition and structure between the groups included in the study. Conclusions: Firing in argon atmosphere does not significantly improve the fracture strength of porcelain bonded to titanium.     

新型分散剂在PP/玻璃纤维/硅灰石复合材料中的应用

选择五种新型结构的分散剂(DZHA–200,DZHA–17,JWF–EBA,JWF–EBC,JWF–EBM),考察分散剂对聚丙烯(PP)/玻璃纤维/硅灰石复合材料加工性能、宏观性能及分散性的影响。实验结果显示,1份分散剂的引入可明显提高和改善复合材料的加工性能、宏观性能和分散性。当加入1份分散剂DZHA–17时,复合材料的熔体流动速率约是未加分散剂时的5.5倍,挤出机扭矩和电流分别降低到7.4 N·m和35 A。断裂伸长率、缺口冲击强度和60°条件下的光泽度也明显提高。五种新型结构分散剂在聚合物复合材料中都显示出润滑性、分散性和偶联性等多功能性,但它们对聚合物复合材料性能影响程度有一定区别。     

Phase morphology development in a low interfacial tension immiscible polyolefin blend during die extrusion and melt spinning

We describe the development of phase morphology in polypropylene (PP)/ethylene–butene copolymer (EBM) blends in both extrusion through dies and in subsequent melt spinning to form filaments. This immiscible blend has a very low interfacial tension around 0.69 dynes/cm. In the die extrusion process, at low extrusion rates, the dispersed PP phase was sheared into fibrils; at higher extrusion rates, the PP fibrils formed an encapsulation layer near the die wall first, then it broke into droplets because of both interfacial tension and long residence time. These droplets agglomerated together to form a network. In melt spinning, the dispersed phase was also drawn down into fibrils, which coalesced into a continuous layer on the outer surface of the filaments at higher drawdown rates. POLYM. ENG. SCI., 50:1969–1977, 2010. © 2010 Society of Plastics Engineers     

Formation of nanoparticle aggregates and agglomerates in polymer nanocomposites and their distinct impacts on the mechanical properties

In this study, the different effects of nanoparticle aggregates and agglomerates on the mechanical properties of polymer nanocomposites are comprehensively investigated. To this end, a specific strategy, based on the equilibrium between the dispersion and cohesion energies in the mixing stage, is proposed using which the content and size of aggregates/agglomerates can be defined. The aggregated/agglomerated networks are considered to place in constrained volumes (CVs), having co-continuous morphology. An equivalent box model (EBM), corresponding to the system, is used to predict the tensile modulus of the nanocomposite. Different test results of HDPE nanocomposite samples, containing 1–3 wt.% of surface-modified silica nanoparticles, prepared by a semi-industrial single screw extruder, are applied to validate the model. Moreover, other data from the literature are also used to further evaluate the accuracy and capability of the proposed analytical method.