A New Kind of Void Soap-free P(MMA-EA-MAA) Latex Particles

Soap-free P(MMA-EA-MAA) particles with narrow size distribution were synthesized by seeded emulsion polymerization of methyl methacrylate (MMA), ethyl acrylate (EA) and methacrylic acid (MAA), and large voids inside the particles were generated by alkali posttreatment in the presence of 2-butanone. Results indicated that the size of void and the particle volume were related with the amount of 2-butanone. The generation mechanism of voids was proposed.

Physical and Chemical Characterizations of Rubber Latex Cup Bottom Oil

Rubber latex is an important economic resource. However, the residues from its harvesting are thrown away, even though they contain lipids that can be recycled. This recovery of the residues from the bottom of the cup requires first and foremost their characterization. The aim of this study is therefore to determine the main physical and chemical characteristics of rubber latex cup bottom oil. Oil’s physical parameters determination shows that it has a density of 951 kg∙m−3, a kinematic viscosity of 48.57 cSt and a water content of 0.0845%. Chemical parameters, meanwhile, indicate that this cup bottom residue has a fat content of 95.96%, an acid number of 2.805 mg KOH/g and an iodine number of 92.42 g I2/100g. Therefore, rubber latex cup bottom oil can be used in the formulation of biofuels, biolubricants, paints, varnishes, alkyd resins, polishing oils, soaps, and insecticides.

基于LaTeX渲染的微积分在线测试小程序设计与实现

为解决传统微积分在线考试系统中数学公式显示不清、存储空间占用大的问题,文章提出了一种基于LaTeX渲染的微信小程序解决方案。相较于传统的图片存储方式,LaTeX渲染可以显著提高公式显示质量,并减少存储空间。该系统可用于微积分课程的过程性考核,实现个性化学习跟踪,提高教学效率。

Natural rubber latex as a potential additive for water-based drilling fluids

The environmental hazards and"carbon footprint"of oil and gas drilling can be significantly reduced by replacing traditional petroleum-based chemical additives with natural materials derived from plants and animals.This paper explored for the first time the interaction mechanism between natural rubber latex(NRL)and bentonite suspensions(BTs)through a series of characterization experiments,as well as the potential applications in water-based drilling fluids(WBDF).The gel viscoelasticity experiments showed that NRL could decrease the consistency coefficient(k)and flow index(n)of BTs,and enhance the shear thinning performance of BTs as pseudo-plastic fluids.In addition,0.5 w/v%NRL not only increased the critical yield stress and strengthened the structural strength between the bentonite particles,but also facilitated the compatibility of pressure loss and flow efficiency.The evaluation of colloidal stability and WBDF performance indicated that NRL particles could promote the hydration and charge stability on the surface of BTs particles,and optimize the particle size distribution and flow resistance of WBDF under the"intercalation-exfoliation-encapsulation"synergistic interaction.Moreover,NRL can improve the rheological properties of WBDF at high temperatures(<150.C),and form a dense blocking layer by bridging and sealing the pores and cracks of the filter cake,which ultimately reduces the permeability of the cake and the filtration loss of WBDF.

Formulation of Motor Oil from Blends of Rubber Latex Cup Bottom Oil (RLBO) and Used Frying Oil (UFO)

Most motor oils are made from mineral oils derived from petroleum, the reserves of which are limited and exhaustible. The aim of this study is to produce and characterize motor oil formulations based on mixtures of rubber latex cup bottom oil (RLCBO) and used frying oil (UFO). The results show that these formulations have a density between 0.91 and 0.92. These densities evolve linearly with the proportion of cup bottom oil and temperature. Similarly, the kinematic viscosity of the blends follows an exponential relationship with temperature. By plotting the logarithm of these kinematic viscosities against the inverse of the temperature, we were able to determine the activation energy of the various blends and deduce that the formulations behave Newtonian.

Influences of Electrolytes on the Soap-free Emulsion Copolymerization of St-MMA-AA

Monodisperse functional polymer microspheres with different particle size and with clean surface were prepared by batch soap-free emulsion polymerization of styrene, methyl methacrylate and acrylic acid in the presence of salts, and the influences of type and amount of electrolytes on polymerization process and particle morphology were investigated. Results showed that there was a critical concentration for different electrolyte to make polymerization process and the resultant emulsion stable, and the particle size increased with the increase of electrolyte concentration. The effect of metal ions was Ca^2＋〉〉K^＋〉Na^＋〉Li^＋, and the effect of haloids was Br〉Cl〉F. Keywords： Electrolyte, soap-free emulsion polymerization, polystyrene, latex particle morphology.

Preparation of multihollow P(St-MAA) particles by sequence soap-free/soap emulsion polymerization and followed by stepwise alkali/acid posttreatment

The effects of ionic emulsifier, sodium dodecylbenzene sulfate (SDBS), on the formation of the multihollow structures in sub-micron sized polymer particles produced by alkali/acid posttreatment were investigated. The original latex particles with narrow size distribution were synthesized by a new sequence emulsifier-free/emulsifier emulsion copolymerization of styrene (St) and methacrylic acid (MAA). Results indicated that the pore size decreased and the pore number increased with the increase of SDBS amount, and the morphology of the posttreated latex particles was also significantly influenced by the introducing time of SDBS in the preparation of the original latex particles, and a suitable introducing time was 3 h of polymerization. (c) 2007 Cheng You Kan. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

SYNTHESIS OF SOAP-FREE ACRYLIC HYDROSOLS

Poly(methyl methacrylate/ethyl acrylate/acrylic acid) hydrosols were prepared by employing soap-free polymerization, and (acrylic acid/butyl acrylate) oligomer was used as the polymeric surfactant. The effect of reaction condition on the morphology and particle size of the hydrosols was investigated. The minimum amount of acrylic acid in the hydrosols is 2%. The maximum weight average molecular weight (M-w) of polymer that assures soap-free emulsion conversion into hydrosol is about 1.2 x 10(5)-1.3 x 10(5). The particle transforming process was investigated, and an obvious change of particle diameter and morphology was observed.

Preparation of Self-crosslinked Fluorocarbon Polymer Emulsion with Core-shell Structure by the Method of Soap-free Emulsion Polymerization

Using methyl methacrylate （MMA）, butyl acrylate（BA） and hexafluorobutyl acrylate（HFBA） as main raw materials, we prepared self-crosslinked fluorocarbon polymer emulsion with core-shell structure via soap-free emulsion polymerization when the conception of particle design and polymer morphology was adopted. Moreover, the influence of mole ratio of BA to MAA, pH value on the oligomer was studied. And the effects of the added amount of oligomer, self-crosslinked monomer and HFBA, mass ratio of BA to MMA, reaction temperature and the initiator on the polymerization technology and the performance of the product, were investigated and optimized. The structure and performance of the fluorocarbon polymer emulsion were characterized and tested with FTIR, TEM, MFT and contact angle and water absorption of the latex film. The experimental results show that the optimal conditions for preparing fluorocarbon polymer emulsion are as follows： for preparing the oligomer, tool ratio of BA to MAA is equal to 1.0 ： 1.60, and pH value is controlled within the range of 8.0 and 9.0; for preparing fluorocarbon polymer emulsion, the added amount of oligmer[P（BA/MANa）] is 6%; mass ratio of BA to MMA is 40 ＂ 60; the added amount of self-crosslinked monomer is 2%, the added amount of HFBA is 15 %; reaction temperature is 80 ℃; the mixture of potassium persulfate and sodium bisulfite is used as the initiator. The film-forming stability of the fluorocarbon polymer emul- sion and the performance of the latex film, which is prepared with the soap-free emulsion polymerization, are better than that prepared with the conventional emulsion polymerization.

PREPARATION AND CHARACTERIZATION OF AFFINITY POLYMER BASIC MICROSPHERES BY SOAP-FREE EMULSION POLYMERIZATION

Poly(styrene-co-glycidyl methacrylate) latex microspheres with uniform size and high-density epoxy groups on the surface were prepared by soap-free emulsion polymerization with batch wise operation mode in the presence of 2.2′- azobis(2-methylpropionamidine) dihydrochloride as an initiator.The kinetics of soap-free emulsion polymerization and the effects of polymerization factors were examined.In addition,the optimum polymerization conditions of poly(styrene-co- glycidyl methacrylate) latex microspheres for...

Synthesis and Characterization of Poly (Methyl Methacrylate)/Polyethylenimine Grafting Core-Shell Nanoparticles for CO2 Adsorption Using Soap-Free Emulsion Copolymerization

Unlike previous emulsion polymerization, we used grafting reactions in soap-free emulsion systems. In this study, we synthesized grafted PMMA/PEI core-shell nanoparticles by varying the MMA/PEI content and molecular weight of PEI (Mn = 600, 8000, and 10,000). The size and morphology of the core-shell nanoparticles were characterized by a particle size analyzer and scanning electron microscopy. The nanoparticles were 178 - 408 nm in diameter and swelled in water or methanol by 30 - 75 nm. The size of the nanoparticles increased with MMA contents, whereas the size distribution progressively became homogeneous with increasing molecular weight of PEI. Lastly, we measured CO2 adsorption capacity of the grafted PMMA/PEI core-shell nanoparticles, and we found the capacity to be limited at a level of 0.69 mg, which occurred for nanoparticles prepared from emulsions at a pH value of 11.

INFLUENCES OF ACID POST-TREATMENT ON THE MORPHOLOGY OF SOAP-FREE P(MMA-EA-MAA)PARTICLES PREPARED BY SEEDED EMULSION POLYMERIZATION

Soap-free poly（methyl methacrylate-ethyl acrylate-methacrylic acid） latex particles with narrow size distribution were synthesized by seeded emulsion polymerization, and the porous particles were created by a stepwise alkali/acid treatment method. Effects of acid treatment conditions on the particle morphology were investigated. Results show that one to three pores were formed inside most of particles after post-treatment. At pH 7.0, when the treatment temperature was lower than 70℃, the size of particles and the volume of pores remained almost unchanged, and these two values increased significantly when the temperature was higher than 70℃. Both the particle size and the pore volume decreased with the increase of initial pH value and treatment time in the acid treatment. As the pH was below 4.0 and the treatment time was longer than 180 min, the particles shrunk in size.

Toxic Effects of Ficus benghalensis Latex Based Combinatorial Formulations on Various Enzymatic Parameters in Indian White Termite Odontotermes obesus

In the present investigation, various bioassays were conducted to evaluate the alteration in levels of various enzymes i.e. alkaline phosphatase, acid phosphatase, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and acetylcholinesterase. For this purpose worker termites were treated with sub-lethal doses of 40% and 80% of 24 hrs LD50 of latex-based combinatorial formulations and observations were taken at 4 hours intervals up to 24 hours. Ficus benghalensis crude latex and its combinatorial mixtures, like C-MLT-A, CU-MLT-A, AQ-MLT, P-MLT and EA-MLT significantly altered the level of enzymes in Odontotermes obesus and this effect found time and dose-dependent. Reduction or increase in enzymes was calculated by using the corresponding control. The maximum decrease in acid phosphatase level was observed at 16 h when termites were treated with 80% of LD50 of B-MLT-B and P-MLT i.e. 82.84% at 16 h of treatment. A similar dose caused a very slight decrease in glutamate pyruvate transaminase at 4 h of treatment but with the increase in time. Further decrease was noted in other successive treatments that were significant at p > 0.05. Similarly, 40% and 80% of LD50 of the C-MLT-B mixture caused significant (p > 0.05) decrease in alkaline phosphatase and acid phosphatase level at 16 h treatment i.e. 93.42%, 89.46% and 95.89%, 88.17% respectively. The level of acetylcholinesterase was also found to be decreased when termites were treated with 40% and 80% of LD50 of C-MLT-B mixture i.e. 92.72% and 97.27% respectively. All the above alterations noted in levels of various enzymes confirm the action of latex ingredients on worker termites that were anti-feedant or deterrent types. These ingredients can be used to control not only termites but also other phytophagous insects.

基于LaTeX的高等数学题库建设与试卷生成

题库管理与出试卷是高校老师工作中的重要组成部分.传统的管理与操作方法费时费力,同时在试题重复率、格式化与标准化等方面相对难以控制.针对中文理工科组卷,利用Te X系统实现题库管理与组卷,能大大减轻老师工作量.在分析高校题库与试卷管理现状及高校理工科试卷特点等基础上,利用LaTeX排版系统和Exam文档类制作与生成题库,利用LaTeX实现自动编号、一键生成试卷和参考答案,以及数学公式、图表等格式化处理,从而形成一整套题库管理与出卷系统.

Defensive Role of Plant Latex on Insect Pests’ Suppression: A Critical Review

Over 350 million years have passed since the documentation of the first interaction between plants and insects. Numerous plant defense qualities and associated counter-adaptive features have developed as a result of these interactions between insects and plants. These characteristics might be either morphological or biological in nature. One of the most significant and useful biochemical characteristics in plants is latex. Latex has a sticky property due to presence of secondary metabolites in it, which aids in entangling or sealing the mouthparts of small insects. These metabolites also chemically interact with the insects interfering with crucial bodily processes. Plant latex has amazing properties that help protect plants from insects and inhibit them in general. It may be possible to control insect pests in a natural, secure, and long-lasting manner by correctly identifying plant latex with strong insecticidal properties and developing formulations of plant latex.

Effect of Ficus benghalensis Latex Based Combinatorial Formulations on Various Bio-Molecules in Indian White Termite Odontotermes obesus

In present investigation, various bioassays were conducted to evaluate the alteration in levels of certain biomolecules, such as glycogen, protein, amino acid, DNA, RNA and lipids. For this purpose, worker termites were treated with sub-lethal dose 40% and 80% of 24 hrs LD50 values and observations were taken at 4 hrs interval up to 24 hrs. Crude latex and its combinatorial mixtures, like S-MLT-A, B-MLT-A, C-MLT-A, CU-MLT-A, AQ-MLT significantly altered level of bio-molecules in Odontotermes obesus. This effect was found time and dose dependent. Reduction or increase in biomolecules was calculated by using corresponding control. Maximum decrease in glycogen level was observed at 16 h when termites were treated with 80% of LD50 of Ficus benghalensis aqueous extract i.e. 56.88% at 16 h of treatment. A similar dose caused very slight decrease in lipid contents at 4 h of treatment but it was found further significantly (p > 0.05) decreased in other successive treatments. 40% and 80% of LD50 of C-MLT-B mixture caused significant (p > 0.05) decrease in DNA and RNA level at 16 h treatment. The level of DNA and RNA level was recorded 83.90%, 90.18% and 85.42% and 74.05% respectively. Similarly, total proteins were also found to be decreased with 40% and 80% of LD50 of C-MLT-B mixture i.e. 71.47% and 66.45% respectively. All these alterations found in levels of various bio-molecules confirm the action of latex ingredients on worker termites that was antifeedant or deterrent types. These ingredients can be used to control not only termites but also other phytophagous insects in a sustainable and eco-friendly way.

Comprehensive treatment of latex wastewater and resource utilization of concentrated liquid

Latex wastewater is a kind of refractory organic wastewater containing high concentrations of organics and ammonia nitrogen.In this work,the combined process of forward osmosis(FO)and reverse osmosis(RO)was designed to treat the latex wastewater in the whole process,achieving the water recovery rate of 99%and basically no waste discharge after the catalytic oxidation process.The turbidity of the latex wastewater was decreased to below 1 NTU by microfiltration pretreatment,and then using MgCl_2 worked as the draw solution for FO process to treat the latex wastewater.Different operation conditions including adding acid or scale inhibitor as the pretreatment methods were conducted to improve the treatment performance of the combined process.After the treatment of the whole process,the concentration of COD was less than 20 mg·L^(-1),the concentration of NH_3-N was less than 10 mg·L^(-1),and the concentration of TP was less than 0.5 mg·L^(-1)for the treated latex wastewater.The water quality met standards of industrial water reuse after the complete analysis of the treated latex wastewater,meanwhile,useful substances of L-Quebrachitol(L-Q)were successfully extracted from the concentrated solution.Therefore,the combined process of FO and RO could realize the efficient treatment and reuse of latex wastewater,which provided with some important guidance on the industrial application.

Mechanical Characterization of Rubber Latex-Based Carpets (Hevea bresiliensis): Influence of Rubber Latex Content and Fiber Fabrics (Cotton and Mosquito Nets) on Wear Resistance of Rubber Latex-Based Carpets

This work focuses on the development of carpets from sand, fabrics of cotton fiber and mosquito nets and rubber latex. Following a study on the choice of the best formulations, the quantity of rubber latex used for shaping varies between 14% and 18% (latex/sand + latex ratio) for the carpet with the fabric of mosquito nets and between 16% and 18% for the one made with the fabric of cotton fiber. Thus, with a mixture of sand, fiber fabrics (cotton and mosquito nets) and rubber latex, carpets were developed. In addition, the wear test carried out on these samples indicates that it is possible to produce carpets with the new material made of rubber sand and latex: SABLATEX At room temperature. Following the characterization test, it resorts to only 16% latex with cotton fiber fabric, allowing to have carpets with good mechanical characteristics.

胶乳增强免疫比浊法NSE诊断试剂盒性能验证及临床应用

目的对胶乳增强免疫比浊神经元特异性烯醇化酶(neuron-specific enolase,NSE)试剂盒进行性能验证。方法按照CNAS-GL037:2019《临床化学定量检验程序性能验证指南》、WS/T492-2016《临床检测定量测定项目精密度与正确度性能验证》并结合试验工作,重新设计了检验方法,在贝克曼库尔特AU5800全自动生化分析对北京九强金斯尔NSE胶乳增强免疫比浊法试剂盒的正确度、精密度、线性范围、可报告范围和生物参考区间等性能进行验证和评估,并与对应罗氏电化学发光法试剂盒进行方法学比对。测试结果与厂家所给出的产品分析性能以及美国国家卫生委员会临床检测中心(National Center for Clinical Laboratories,NCCL)的相关指标进行了对比。结果5个水平的正确度偏倚分别为1.74%、-1.42%、-0.88%、-3.09%和-0.90%;2个水平的批内及批间精密度的变异系数(coefficient of variation,CV)分别为1.85%和0.88%(判断标准CV<7.5%),4.99%和3.34%(判断标准CV<10%);线性范围(3.5~148.1ng/mL)验证回归系数a值为0.9894,R2=0.9978;最大稀释倍数为8倍,临床可报告上限为1165.2ng/mL;厂家提供的生物参考区间为0~16.3ng/L,符合率R为100%,各性能均通过验证。此外,与罗氏电化学发光试剂盒进行方法学比对,其相关性分析结果为:两种方法的相关性(R2=0.989)、一致性(CCC=0.984)均较好,在临床判定效果上同Roche的电化学发光试剂盒相比,免疫增强比浊方法阳性符合率为95.74%,阴性符合率为96.23%,两者测定值接近,相关系数达0.9894。结论基于全自动生化分析平台测定的NSE胶乳增强免疫比浊试剂盒,各性能均可以较好地满足临床使用要求,且与电化学发光法检测结果一致性较好,有望进一步推进NSE国产体外诊断试剂盒的临床应用。

改性干粉型聚合物水泥砂浆试验研究

本文研究两种不同的可再分散乳胶粉(醋酸乙烯-乙烯共聚物和醋酸乙烯/叔碳酸乙烯酯共聚物)对干粉型聚合物水泥砂浆力学性能、粘结强度、吸水率、干燥收缩的性能影响。结果表明,可再分散乳胶粉的掺量、类型对聚合物水泥砂浆的性能影响较大,力学性能较普通水泥砂浆有明显的提升和改善。可再分散乳胶粉的加入虽然降低了砂浆的抗压强度,但显著提高了抗折强度和折压比,改善了砂浆的柔韧性和抗裂能力;砂浆的干燥收缩、粘结强度和吸水率等性能均有较为明显的改善。