制备方法对GO/P(NIPAM-MA)水凝胶La3+吸附性能的影响

用冷冻聚合法和非冷冻聚合法制备了氧化石墨烯/聚(N-异丙基丙烯酰胺-顺丁烯二酸)(GO/P(NIPAM-MA))水凝胶,比较制备方法对GO/P(NIPAM-MA)水凝胶La³⁺吸附能力的影响,发现通过冷冻聚合法合成的水凝胶,具有更加优异的溶胀-退溶胀性能和吸附性能。NIPAM与MA摩尔比为10∶1的冷冻聚合法水凝胶,在370 mg/L的LaCl₃溶液中平衡吸附量为(29.87±0.073)mg/g,而相同条件下的非冷冻聚合法水凝胶平衡吸附量仅为(20.29±0.395)mg/g。冷冻聚合法水凝胶的Freundlich等温线拟合参数n值随着MA含量的增加呈线性增加,而非冷冻聚合法水凝胶增加幅度小于冷冻聚合法。经过5次吸附-解吸循环,冷冻聚合法水凝胶的形状和体积没有明显变化且吸附能力没有明显下降,而非冷冻聚合法水凝胶经过3次吸附-解吸循环就出现破碎,无法再使用。冷冻聚合法合成的GO/P(NIPAM-MA)水凝胶具有La³⁺平衡吸附量大、可重复使用等优点。     

日本川重车体(株)玻璃钢冷冻车箱介绍

一九七九年九月日本神户工业技术展览会在天津展出期间,就玻璃钢车箱冷冻车(FRP—冷冻车)进行了专题技术座谈。座谈内容包括三部分:①玻璃钢冷冻车箱;②冷冻机;③生鲜食品、冷冻食品的低温输送和冷冻车。现将玻璃钢冷冻车箱座谈的心得体会作一介绍。     

硝酸磷肥制造过程——直接冷冻法(kaltenbach—SCHZ流程)

捷克在罗佛雪(Lovosice)(地近布拉格)采用规模700吨/日直接冷冻法制硝酸磷肥厂已正常运行一年多。现捷克、西德将采用此流程建若干新厂。该法系捷克Sereroceske Chcmicky Zavody(SCHZ)与法国Kaltenbach& Cie合作发明的新方法,是Odda流程的改进,主要将间接冷冻结晶分离Ca(NO_3)_2改为直接冷冻。     

硝酸磷肥的生产与发展(续)

4.2冷冻法硝酸磷肥装置实例 4.2.1冷冻法简介 冷冻法是生产硝酸磷肥使用最广、建厂规模最大的一种方法,它是用物理冷冻方法除去可溶性CaO,亦称Odda法.其过程为:在不锈钢制的酸解槽内,用HNO3≥53%(质量分数,下同)的硝酸分解磷矿;酸解液分离酸不溶物后,送至不锈钢制的多台结晶槽内,用温度为-15C的冷却剂(20%NH3水或35%Ca(NO3)2溶液)进行间接冷却,使酸解液温度降到-5℃左右;此时,CaO就以Ca(NO3)2@4H2O形式结晶析出,然后,在过滤机上分离,并用冷硝酸与冷水洗涤,洗酸与洗水返回酸解槽内,分离结晶后的母液主要组成为HaPO4、HNO3和未结晶的Ca(NO3)2等.     

非晶态Ni(OH)2电极材料的制备工艺

采用微乳液快速冷冻沉淀法制备非晶态Ni(OH)2. 通过单因素及正交实验研究反应体系的pH值、反应温度和时间等因素对制备的非晶态Ni(OH)2电化学性能的影响. 结果表明,主要影响因素为pH值,其次为反应温度和时间. 采用TX-100/正丁醇/环己烷/水体系,控制TX-100与正丁醇的体积比为1:15,W值(水与表面活性剂质量比)为15.1,pH为12,反应时间2 h,反应温度55℃的条件下进行反应,放入0~5℃的超低温恒温槽中快速冷冻沉淀,合成出Ni(OH)2非晶相粉体电极活性材料,该材料的放电比容量达333.22 mA×h/g,具有较高的电化学容量. 初步探讨了微乳液快速冷冻沉淀法制备非晶态Ni(OH)2粉体的作用机理.     

湿度差驱动下溶液蒸发冷冻过程中冰体的发展规律

针对湿度(绝对湿度)差驱动下溶液的蒸发冷冻过程进行了分析研究,在热质平衡理论的基础上,考虑溶液表面冰体的形面变化特征,建立了蒸发冷冻过程中溶液表面冰体生长的热力学非稳态模型,分析了不同蒸发冷冻时刻,气-液界面间湿度(绝对湿度)差、气流速度以及气-液界面间质扩散对溶液表面冰体发展分布的影响,研究表明湿度(绝对湿度)差、气流速度和质扩散系数对溶液的蒸发冷冻作用明显。该理论模型及研究结果为强化湿度差驱动下溶液的蒸发冷冻及工程应用提供了理论指导和依据。     

热风与真空冷冻联合干燥毛竹笋的试验研究

对毛竹笋进行了热风与真空冷冻联合干燥(AFD)的研究，应用热风与真空冷冻(AD FD)和真空冷冻与热风(FD AD)两种方式做不同转换点试验，将得到的产品分别与完全的热风干燥和冷冻干燥的产品比较其能量消耗和物化特性，并对它们的产品进行理化分析，确定了AFD联合干燥的方式和最佳转换点，得出了真空冷冻与热风(FD AD)联合干燥的产品接近完全真空冷冻干燥(FD)产品的结论，AFD联合干燥对于提高脱水笋干的质量、节省能量消耗是有效的。     

基于模拟核算的煤化工浓盐水分盐工艺选择

在概要对比煤化工浓盐水零排放及分盐工艺的基础上,就煤化工浓盐水处理实例,以盐资源化率、产品纯度为评价指标对(NF+热法结晶)分盐、(NF+冷冻+热法)分盐、(单纯冷冻+热法)分盐三种工艺进行模拟核算,综合考虑运行成本、投资等,优选出(NF+冷冻+热法)分盐工艺。对分盐系统设计提出了几点建议。     

阿科玛(常熟)有机过氧化物厂开业

10月25日,阿科玛在中国江苏省常熟市举行了有机过氧化物厂开业典礼。阿科玛(常熟)有机过氧化物厂按时成功启动,实现既定的产品规格。该厂的初步产能为3000吨/年,提升了阿科玛在亚洲地区的整体实力。阿科玛的客户服务、反应能力与冷冻物流方案确保公司在中国、台湾与东南亚地区的有机过氧化物(用于聚合物)市场上居于领先地位。阿科玛是世界上第二大的有机过氧化物生产厂家,在全球拥有11家有机过氧化物的生产基地,包括亚洲(中国、韩国、印度与日本)、美国(德克萨斯州与纽约州)以及欧洲(德国、法国与意大利)。阿科玛在美国、印度与欧洲基地(包…     

临界条件(0℃)下溶液蒸发冷冻过程中的传质规律

通过对相际间力学特性的分析,结合湍流的流动特征,考虑了冰体存在孔隙和毛细作用,给出了临界条件(0℃)湿度差驱动下溶液蒸发冷冻过程中的质扩散分析模型,并对溶液在不同状态下(液态、液固共存和固态)气流界面间的质扩散变化规律进行了研究,结果表明,随着溶液从液态向固态的转变,其表面质扩散系数逐渐减小,即表面质扩散能力逐渐减弱,因此,对于溶液自身蒸发冻结过程而言,为了强化溶液表面的质传递和冻结,应控制冻结过程中溶液表面的结冰状况。这一研究结果为蒸发冷冻传质的研究以及强化蒸发冻结的工程应用提供了理论指导和参考。     

聚合氯化铝

<正> 一、聚合氯化铝的净水性能随着工业的迅速发展,水源污染甚为严重,故需要净化的污水种类繁多。且工业用水的水质要求亦越来越高。于是,一些高效的净水药剂便应运而生。聚合氯化铝,便是七十年代以来,净水药剂上一个异军突起的新品种。它可以有效地净化浊度较高的河水,对水中微生物、细菌、藻类,去除率达90%,放射性物质去除率达80%。药效比一般传统净水剂硫酸铝高2～4倍。甚至含Pb~(++)、Cr~(+++)等毒性较大的重金属污水,去除率亦达90%。并能使造纸废水色度降低七倍。聚合氯化铝的另一特点是它对浊度高、色度大的原水仍具有较高的净化效果,而且大量投加,也能保持水质     

Dispersion of Poly(phenylene ether) in a Poly(phenylene sulfide)/Poly(phenylene ether) Alloy

We have devised and developed a new method for the preparation of a poly(phenylene sulfide)/poly(phenylene ether) (PPS/PPE) alloy, which has micro‐dispersed PPE in the PPS matrix. PPS was chemically treated to activate the reactivity of the PPS end‐group by extrusion in the presence of diphenylmethane diisocyanate (MDI) in its molten state at 300°C. The reactive processing of the MDI‐treated PPS with maleic anhydride‐modified PPE gave a PPS/PPE alloy with micro‐dispersed PPE in the PPS matrix. The PPS/PPE alloy showed mechanical properties superior to those of PPS at elevated temperature (150°C) and also showed precision‐molding ability superior to that of PPS.     

苯乙烯—异戊二烯—苯乙烯热塑性嵌段共聚物

简介近年来国外SIS生产状况、生产工艺技术经济评估、SIS的基本性能和应用以及国外技术发展趋势,井对国内SIS产品开发作出预估。     

Poly(alkylnylstannanes)

Summary The synthesis of poly(alkynylstannanes) was achieved by the step-growth polymerization of bisaminostannanes and ,-diynes. This is a new class of organotin polymers containing tin-alkyne linkages in the polymer backbone. The polymers were obtained in good yield, albeit with relatively low molecular weight. The polymers underwent crosslinking on standing to give insoluble material and required stabilization with radical inhibitors. The thermal properties of these materials, and the influence of the group pendent to tin are discussed.     

Poly(ortho-vinylbenzophenone)

This article reports the synthesis and free radical polymerization of ortho-vinylbenzophenone. The glass transition temperature T_g of the homopolymer is 136°C. The products synthesized appeared to be atactic and amorphous. The Mark-Houwink constants for poly (o-vinylbenzophenone) in tetrahydrofuran are K = 4.2 × 10^?2 cm³ g^?1 and a = 0.765. The pre-exponential constant under theta conditions, K_θ, is estimated to be 5.93 × 10^?2 cm³ g^?1. The ratio of unperturbed dimensions of the actual polymer and free rotating analogue chain is 3.93, which is almost double that of polystyrene. The Flory-Huggins interaction parameter for poly $\text{(o-}\text{vinylbenzophenone}\text{)}\text{tetrahydrofuran}$ is 0.48 at room temperature. The $\text{k}{}_{\mathrm{<mtext>p</mtext>}}\text{k}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}{}_{\mathrm{<mtext>t</mtext>}}$ ratio at 60°C is $\text{1.1 × 10}{}^{\mathrm{?2}}\text{l}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{mol}{}^{\mathrm{<mtext>?1</mtext><mtext>2</mtext>}}\text{s}{}^{\mathrm{<mtext>?1</mtext><mtext>2</mtext>}}$. In free radical copolymerizations with styrene at 70°C, r₁ (o-vinylbenzophenone) = 1.216, r₂ = 0.751. This copolymerizations is virtually random.     

聚β-羟基丁酸酯和聚碳酸亚丙酯的共混体系研究

采用溶剂挥发法和熔融共混法分别制备了聚β-羟基丁酸酯(PHB)和聚碳酸亚丙酯(PPC)的共混物,采用DSC、X-射线衍射、扫描电镜、偏光显微镜等手段系统研究了共混物配比对体系热、力学性能、形貌的影响.结果表明,随着共混物中PHB含量的增加,共混物断裂强度增大,PPC的加入可明显改善材料脆性,断裂伸长率增大.PPC的存在可以抑制PHB的结晶过程,降低PHB的熔点,拓宽PHB的熔融加工窗口.上述共混物在可降解塑料领域具有良好的应用前景.     

Synthesis of Poly(∊-caprolactam) and Poly(ethyleneterephthalate) Star Polymers

Abstract

Two kinds of condensation-polymerization star polymers were prepared. One kind is star nylon-6 and the other is star PET. In both star polymers the arms are flexible and the cores are rigid aromatic fractal polyamides (FPs). The FPs are porous and of size comparable to the size of the flexible arms of the stars. The FPs are decorated with reactive sites appropriate for the grafting or growing of star arms. In the case of star nylon-6, two preparation methods are described: grafting of pre-existing nylon chains onto FPs, and growing nylon-6 arms from the FPs by polymerization of caprolactam in the presence of FPs. In the case of star PET, grafting of pre-existing PET chains was employed in order to create the star polymers. Various characterization techniques indicated that in the grafted star polymers up to 10 arms could be attached to each FP core. The results indicate, however, that fine control of the star formaton was not achieved yet. The required conditions to reach this target are spelled out.     

New Miscible Poly(ether imide)/Poly(phenyl sulfone) Blends

Summary: Blends of PEI and PPSU were prepared directly during the plasticization step of an injection molding process throughout the full composition range. The molded blends were transparent and showed a single glass transition and no dispersed phase by SEM. These characteristics did not allow the presence of a single miscibilized phase to be inferred unambiguously due to the very similar T_gs and refractive indices of the two components of the blends. Miscibility was inferred after close observation of the position, height and area of the enthalpy relaxation peak of the 50/50 blend. The modulus of elasticity and yield stress changed linearly with composition, leading to polymer materials with intermediate characteristics. The linearity was attributed to the lack of decrease in free volume induced by mixing and to the similar orientation of the components before and after mixing. The PPSU presence only slightly reduced the known tendency towards brittle fracture of PEI under notched impact conditions, but the presence of a single amorphous phase led to an expected ductile behavior of the blends close to that predicted by the single rule of mixtures.

Break stress (?) and break strain (○) of PEI/PPSU blends as a function of composition.     

聚乳酸/聚丁二酸丁二醇酯共混物的研究

通过熔融共混制备了聚乳酸(PLA)/聚丁二酸丁二醇酯(PBS)共混物,采用扫描电子显微镜、差示扫描量热仪、旋转流变仪对其相容性、热性能和黏度等进行了研究,并研究了PBS的加入对PLA力学性能的影响。结果表明,PLA和PBS之间是部分相容的,PBS的少量添加并不影响PLA的拉伸强度,且其冲击强度随着PBS含量的增加呈先上升后下降的趋势,当PBS含量为10份时,共混物的冲击强度最好;与纯PLA相比,共混物的黏度有所增加,且随着PBS含量的增加,共混物的黏度逐渐增大;PBS的添加起到异相成核作用,促进了PLA的结晶。