聚醚砜和聚醚醚酮

商品牌号为 Victrex~(R)的聚醚砜(PES)是典型的工程塑料,其韧性高、强度大、刚性强,具有极好的耐高温性能,且可燃性低,发烟少。PES 可制造线圈架、连结器、终端部件、热水表、医用聚合物涂料等。但 PES是无定形塑料,具有无定形树脂的特性。聚醚醚酮(PEEK)是结晶性耐高温工程塑料,使用温度可达300℃,其机械强度和耐化学腐蚀性能超过 PES。1.加工过程PES 和 PEEK 可用常规的设备进行模压、注射、挤出等加工,并可回收利用。加工时间与其它常规工程塑料相近。加工前都     

甲基取代杂萘联苯型聚芳醚的合成、表征及性能

以自制的新型甲基取代类双酚 4 - ( 3-甲基 - 4 -羟基苯基 ) - 2 - 3-二氮杂萘 - 1-酮 ( OM- HPPZ)为单体与4 ,4′-二氟二苯酮、4 ,4′-二氯二苯砜进行亲核缩聚反应 ,制得了一类新型甲基取代聚芳醚酮、聚芳醚砜及其共聚物聚芳醚砜酮树脂。在适宜的聚合条件下 ,获得了高分子量的聚合物 ,聚醚酮的特性粘度可达0 .70× 10 2 m L/ g;通过调节砜酮比例 ( S/ K)可获得不同分子量、不同玻璃化温度的共聚物 ( PPESK)。利用 DSC、TGA研究了聚合物的耐热性能 ,结果表明 ,新型聚芳醚玻璃化温度高 ( 2 5 2℃～ 2 90℃ ) ,耐热稳定性好 ( 5 %热失重温度高于 4 16℃ ) ,在氯仿、DMAc等极性有机溶剂中可溶解成膜 ,以 FT- IR和 1H-NMR研究了类双酚单体 OM- HPPZ和聚合物的结构 ,证明与设计结构完全一致     

聚醚醚酮的合成与表征

以二苯砜为溶剂,在无水碳酸钾/碳酸钠的催化下,通过对苯二酚与4,4-二氟二苯甲酮进行亲核取代反应,合成了特性黏度为0.89的聚醚醚酮(PEEK);探讨了溶剂与反应温度对分子量的影响.通过IR、DSC、TG和XRD对其结构与性能进行了表征,确定其结构为PEEK;TG测试表明,在N2气氛下开始分解温度为541℃,且到1200℃时也没分解完全;DSC和XRD衍射图表明其为半晶态聚合物,且由DSC曲线可知其熔点(Tm)为347℃.     

含PDMS聚砜膜的制备及其对CO_2/CH_4分离性能的影响

选用聚二甲基硅氧烷(PDMS 4200)、六氟双酚A及4,4-二氟二苯砜作为单体,通过缩聚反应制备了PDMS 4200含量为5%(摩尔分数,以下同)和10%的共聚物[聚砜(PSF)-PDMS]膜,利用核磁共振氢谱仪和傅里叶变换红外光谱仪对共聚物结构进行了表征。考察了PDMS 4200含量(0~10%)、温度(298~328K)对CO_2和甲烷气体渗透性能的影响。     

几种甲基取代的新型可溶性聚芳醚酮醚砜醚酮的合成与表征

在无水A lC l3及DM F存在下,将4,4′-二(4-氯甲酰苯氧基)二苯砜(SPC l)、4,4′-二(3-氯甲酰苯氧基)二苯砜(SM C l)分别与2-甲基二苯醚(o-M DPE)和3-甲基二苯醚(m-M DPE)在1,2-二氯乙烷中进行低温溶液缩聚,合成了4种新型可溶性的甲基取代聚芳醚酮醚砜醚酮(M-PEKESEK)。DSC,TG,FT-IR及W AXD等测试表明,4种聚合物均为无定型结构,其玻璃化转变温度(Tg)介于157℃~167℃,在氮气气氛中5%的热失重温度(Td)均在465℃以上,易溶于氯仿和DM F、DM SO等强极性非质子有机溶剂中。     

含磷环氧树脂固化剂的合成表征与环氧树脂复合材料阻燃性能的研究

以季戊四醇(PER)、三氯氧磷(POCl_3)和乙二胺(EDA)为原料合成了一种阻燃固化剂聚乙二胺季戊四醇螺磷酸酯(PES),并通过红外光谱(FT-IR),核磁共振(1 H NMR)、质谱(ESI-MS)和热重分析(TGA)对其结构和热性能进行了表征。并以PES和4,4-二氨基二苯砜(DDS)为固化剂,双酚A型环氧树脂(E-51)为基体树脂,制备了不同含磷量的阻燃环氧树脂复合材料。通过极限氧指数(LOI)和垂直燃烧(UL-94)实验表征了环氧树脂复合的阻燃性能,热重分析和扫描电镜研究了阻燃环氧树脂的热性能和残炭形貌。研究发现,随着磷含量增加,阻燃环氧树脂的初始分解温度逐渐降低,但与纯样相比,在600℃时的残炭量显著增加,且随着PES加入量的增大,SEM观察形成的炭层越致密。当磷含量为3.48%时,其LOI值可达28.9,并通过UL-94V0级测试,拉伸强度和冲击强度分别达到了62.76 MPa和6.81kJ/m~2,表明PES是一种良好的环氧树脂阻燃剂。     

P(MMA-MAh)基凝胶聚合物电解质导锂离子性能研究

以甲基丙烯酸甲酯(MMA)和马来酸酐(MAh)单体合成共聚物P(MMA-MAh),并以其为聚合物基体制备了凝胶聚合物电解质。采用傅里叶红外光谱(FT-IR)、差示扫描量热法(DSC)和热失重分析(TGA)对合成共聚物进行了表征,并采用交流阻抗法对制备的凝胶聚合物电解质(GPE)的导锂离子性能作了研究,并且分析了不同温度和配比对其离子电导率的影响。结果表明:成功合成了聚合物P(MMA-MAh),其热分解温度为300℃,玻璃化转变温度为133.9℃,制备的GPE的离子电导率随温度的升高而增大,随聚合物含量的增加而减小,且在研究温度范围内锂离子迁移符合Arrhenius方程。     

PEKS分子结构及其合成的动力学研究

测定两种共单体的相对活性(γ)和两种共单体的单位含量(C_R、C_S),可定量评价聚醚酮砜二元共缩聚的非均一性。发现二氯二苯砜(DDS)与二氟二苯酮(DFK)的相对活性为1.97×10~(-08)exp(9.6×10~3/T。由~(13)C-NMR测定了C_R、C_S。PEKS的链结构按不同的三个部分(P_(RR)、P_(RS)、P_(SS))的平均链段长度值(L_R、L_S)来表征说明。 在不同反应温度及共单体的不同比例,采用~(13)C-NMR和DSC研究了合成的一系列PEKS的微观非均一性,并指出共单体和反应温度对链结构影响很大,由T_(?)温度变化能看到链结构对T_(?)的直接影响。     

磺化聚砜膜材料的制备与性能研究

磺化聚砜是制备亲水性滤膜的优良材料。首先以发烟硫酸为溶剂、4,4’-二氯二苯砜(DCDPS)为原料成功制备了磺化单体3,3’-二磺酸钠-4,4’-二氯二苯砜(SDCDPS),并确定了最佳磺化条件,n(SO3)/n(DCDPS)=3.5,反应温度110℃,反应时间20h。以SDCDPS为单体通过亲核缩聚反应合成了一系列不同磺化度的磺化聚砜膜材料,利用红外光谱及核磁共振光谱对其结构进行了表征。热分析实验表明,该聚合物材料具有较高的分子量和热稳定性。     

聚芳硫醚砜酰胺共聚物的常压合成与表征

以自制的4,4′-二氟二苯酰胺和4,4′-二氯二苯砜及精制工业硫化钠为反应单体,在N-甲基吡咯烷酮中采用分批投料、逐步聚合的方式,进行常压缩聚,合成了线型较高分子量的新型聚芳硫醚砜酰胺共聚物(PA SS/A),在较优的反应的条件下,制得了特性黏数在0.25 dL/g~0.40 dL/g的共聚物。用红外和核磁对聚合物进行了结构表征,用TG、DSC等手段对聚合物热性能进行了测试,用XRD对聚集态结构进行了表征。结果表明,共聚物具有优良的耐热性和局部有序结构;且发现该聚合物的玻璃化温度和热稳定性随着酰胺含量的增加而略微降低。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.