KH550交联改性无溶剂聚氨酯/丙烯酸酯乳液的合成应用

采用原位聚合法,合成了一系列γ-氨丙基三乙氧基硅烷(KH550)改性的无溶剂阴离子型聚氨酯/丙烯酸酯复合乳液(WPUA)。重点考察了KH550用量对WPUA乳液及涂膜性能的影响,通过红外光谱(FT-IR)、热重分析(TGA)、粒度分析仪(DLS)、原子力显微镜(AFM)、吸水率测试等对其相关性能进行了表征。结果表明,KH550反应到聚氨酯链段上且当ω(KH550)=1.05%(占 整 个 反 应 物 总 量,下 同)时,WPUA乳液稳定性较好,平均粒径为104.5nm,其热稳定性也较佳,涂膜表面平坦且较规整,硬度可达2H,耐冲击性合格,附着力达到0级,吸水率低至8.57%。     

GMA改性无溶剂阴离子聚氨酯/丙烯酸酯复合乳液的合成及性能研究

采用原位聚合法,制备得到了无溶剂阴离子聚氨酯/丙烯酸酯(WPUA)复合乳液,系统地研究了GMA用量对WPUA乳液及其膜性能的影响。结果表明,当m(GMA)=10.2%时,WPUA乳液粒径较小且分布窄,平均粒径为141.1nm,且聚合物具有良好的热稳定性,涂膜呈现良好的耐水性和耐醇性,吸水率低至6.85%,涂膜硬度达到2H,附着力达到0级,耐冲击合格。     

环氧树脂改性无溶剂聚氨酯-丙烯酸树脂复合乳液及其性能研究

采用原位聚合法,制备得到系列环氧树脂(E-44)改性的无溶剂阴离子聚氨酯/丙烯酸酯(WPUA)复合乳液。通过傅里叶红外光谱(FT-IR)、热失重分析(TGA)、耐介质性及力学性能测试讨论了E-44用量对WPUA乳液及其膜性能的影响。FTIR表明,E-44中的—OH和环氧基都参与了反应。TGA表明,E-44的加入明显改善了涂膜的热稳定性。另外当W(E-44)=7.6%时,涂膜吸水率为6.13%,吸乙醇率为49.78%,呈现良好耐介质性;且涂膜硬度可达2H,附着力达到0级,耐冲击性合格。     

丙烯酸酯软硬单体含量对PU/PA复合乳液及其表面施胶性能的影响

采用原位无皂乳液聚合法制备了水性聚氨酯-丙烯酸酯(WPUA)复合乳液。分析了软硬单体比例对WPUA乳液粒径、粘度,对胶膜的凝胶率、吸水率和力学性能的影响,并研究了WPUA乳液对纸张的增强作用。研究表明,随着m(MMA)增大,胶粒粒径增大,乳液粘度下降,胶膜凝胶率上升,吸水率先下降后上升,且当m(MMA)为14.37%时,胶膜力学性能最佳。以质量分数为1%的WPUA乳液进行表面施胶,施胶度达37.47s,湿强度达31.61%。当m(MMA)为8.64%时,耐折度达54次。     

无溶剂阴离子聚氨酯/丙烯酸酯乳液的制备及其膜性能研究

采用原位聚合法,以异佛尔酮二异氰酸酯(IPDI)、聚己内酯二元醇(PCL)、二羟甲基丁酸(DM-BA)、甲基丙烯酸羟乙酯(HEMA)、甲基丙烯酸缩水甘油酯(GMA)、甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)等为主要原料制备得到了无溶剂阴离子聚氨酯-丙烯酸酯(WPUA)复合乳液,并系统地研究了n(NCO)/n(OH)(R值)、亲水扩链剂DMBA和硬单体MMA的用量对WPUA乳液及其膜性能的影响。结果表明,WPUA乳胶粒呈核-壳结构,当R=1.2,m(DMBA)=3.1%,m(MMA)=26.6%时,所得的WPUA乳液粒径较小且分布窄,平均粒径为98.98nm,乳胶膜呈现良好的物理机械性能,拉伸强度为17.02MPa,断裂伸长率为109%,吸水率低至6.9%。     

水性聚氨酯丙烯酸酯乳液的制备及性能

目的制备丙烯酸酯改性水性聚氨酯乳液,研究内交联剂对其性能的影响。方法以聚氨酯为种子乳液,以三羟甲基丙烷单烯丙基醚(TMPME)为扩链剂和内交联剂,以甲基丙烯酸甲酯(MMA)及丙烯酸酯丁酯(BA)为丙烯酸酯单体,制备丙烯酸酯改性的水性聚氨酯(WPUA),研究TMPME用量对WPUA及其胶膜性能的影响。结果当TMPME质量分数为3%时,乳胶膜的吸水率可降至7%;对乳胶膜进行热处理可进一步提高膜的耐水性;当TMPME质量分数为2%时,乳胶膜的拉伸强度可提高至8.7MPa,断裂伸长率升高至620%,综合性能最佳。结论引入一定量的TMPME,可以提高WPUA中分子的交联度和膜的致密性,从而显著改善乳胶膜的耐水性和力学性能。     

水性聚氨酯的合成、改性及其在烟包涂料上的应用

为了满足烟包印刷行业低VOC含量的要求,以耐高温聚酯二元醇(NCL2000)作为软段,4,4′-二环己基甲烷二异氰酸酯(HMDI)、亲水扩链剂二羟甲基丁酸(DMBA)、扩链剂1,4-丁二醇(BDO)、后扩链剂乙二氨基乙磺酸钠(AAS)、封端剂丙烯酸羟乙酯(HEA)、甲基丙烯酸甲酯(MMA)作为硬段,制备了无三乙胺、零VOC的水性聚氨酯-丙烯酸酯(WPUA)复合乳液,研究了MMA对WPUA复合乳液的制备及胶膜性能的影响,并通过傅里叶变换红外光谱(FTIR)、热重分析(TGA)等测试手段对WPUA乳液及其胶膜的结构和性能进行分析。结果表明,随MMA添加量增大,WPUA复合乳液平均粒径增大,WPUA胶膜的吸水率随之减小。当热失重率为50%时,MMA改性后的WPUA胶膜比纯水性聚氨酯(WPU)胶膜的分解温度提高了52.85℃。     

苯胺-对苯二胺共聚物改性水性聚氨酯-丙烯酸酯涂层的制备及防腐性能研究

采用微乳液聚合法合成苯胺-对苯二胺共聚物P(ANI-PDA),采用原位乳液聚合法制备水性聚氨酯-丙烯酸酯复合乳液(WPUA),根据物理共混法制备出苯胺-对苯二胺共聚物/水性聚氨酯-丙烯酸酯复合涂层P(ANI-PDA)/WPUA。采用原子力显微镜(AFM)、热重分析(TGA)、吸水率测试、电化学测试和盐雾实验对P(ANI-PDA)/WPUA的形貌、热稳定性和防腐性能进行了表征和测试,研究了P(ANI-PDA)用量对涂层防腐性能的影响。结果表明,随着P(ANI-PDA)用量的增加,胶膜的热稳定性提高,乳胶粒粒径增大,当P(ANI-PDA)用量为1.5%时,胶膜的吸水率最低为4.1%,腐蚀电位为-1.034V,腐蚀电流密度为2.75×10~(-7) A·cm~2,耐盐雾最好,防腐性能最佳。     

交联型水性聚氨酯-丙烯酸酯复合乳液的制备及其胶膜性能研究

采用原位聚合的方法,以异佛尔酮二异氰酸酯(IPDI)、聚碳酸酯二元醇(PCDL-1000)、1,4-丁二醇(BDO)、2,2-二羟甲基丙酸(DMPA)、丙烯酸缩水甘油酯(GMA)等为主要原料,合成交联型水性聚氨酯-丙烯酸酯复合乳液(WPUA)。系统研究了交联剂用量对复合乳液及其胶膜性能的影响,并通过FT-IR、TGA、XRD、SEM表征了复合乳液及其胶膜的结构和性能。结果表明,适度交联能够提高材料的力学性能及耐水性能,当n(GMA)/n(DMPA)=0.1~0.2时,所得WPUA乳液性能稳定,聚合物具有良好的热稳定性及耐水性,吸水率低至5.4%;拉伸强度达到28.9 MPa,较未交联胶膜的拉伸强度提高了173%。     

KH550改性水性聚氨酯膜的结构及表面性能研究

以氨基硅烷偶联剂KH550为封端剂对水性聚氨酯预聚体进行改性,然后进一步乳化制得KH550改性的水性聚氨酯乳液。研究了KH550的用量对乳液的稳定性、改性膜表面结构和改性膜抗水性能的影响。研究结果表明:随着KH550含量的增加,乳液的储存稳定性降低,冻融稳定性提高;聚氨酯膜表面Si-O-Si键的含量逐渐增加;改性膜表面水接触角增大,膜表面的拒水性能提高。并进一步对表面结构和性能之间的关系进行了探讨。     

Fe86Zr5.5 Nb5.5 B3非晶合金的超高压烧结成型

为了获得致密的块状Fe86Zr55Nb55B3纳米晶合金,研究了高压快速烧结工艺参数对样品致密度和α-Fe相晶粒尺寸的影响.结果表明:快淬球磨破碎非晶粉末在5.5 GPa/3min烧结条件下,当Pw=1150 W后,可获得相对密度为98.3%、单相α-Fe纳米晶(16.3 nm)块体合金,且随着Pw和t的增加,样品相对密度和α-Fe相晶粒尺寸均略有增加,样品典型的比饱和磁化强度σs和矫顽力Hc分别为119.6 emu/g,63.8 Oe.     

Thermodynamic properties of Pt5La,Pt5Ce,Pt5Pr,Pt5Tb and Pt5 Tm intermetallics

The Gibbs’ energies of formation of Pt₅La, Pt₅Ce, Pt₅Pr, Pt₅Tb and Pt₅ Tm intermetallic compounds have been determined in the temperature range 870–1100 K using the solid state cell: $$Ta,M + MF_3 /CaF_2 /Pt_5 M + Pt + MF_3 ,Ta$$ . The reversible emf of the cell is directly related to the Gibbs’ energy of formation of the Pt₅M compound. The results can be summarized by the equations: $$\begin{gathered} \Delta G_f^ \circ \left\langle {Pt_5 La} \right\rangle = - 373,150 + 6 \cdot 60 T\left( { \pm 300} \right)J mol^{ - 1} \hfill \\ \Delta G_f^ \circ \left\langle {Pt_5 Ce} \right\rangle = - 367,070 + 5 \cdot 79 T\left( { \pm 300} \right)J mol^{ - 1} \hfill \\ \Delta G_f^ \circ \left\langle {Pt_5 Pr} \right\rangle = - 370,540 + 4 \cdot 69 T\left( { \pm 300} \right)J mol^{ - 1} \hfill \\ \Delta G_f^ \circ \left\langle {Pt_5 Tb} \right\rangle = - 372,280 + 4 \cdot 11 T\left( { \pm 300} \right)J mol^{ - 1} \hfill \\ \Delta G_f^ \circ \left\langle {Pt_5 Tm} \right\rangle = - 368,230 + 4 \cdot 89 T\left( { \pm 300} \right)J mol^{ - 1} \hfill \\ \end{gathered} $$ relative to the low temperature allotropic form of the lanthanide element and solid platinum as standard states The enthalpies of formation of all the Pt₅M intermetallic compounds obtained in this study are in good agreement with Miedema’s model. The experimental values are more negative than those calculated using the model. The variation of the thermodynamic properties of Pt₅M compounds with atomic number of the lanthanide element is discussed in relation to valence state and molar volume.     

GAMS5

The construction of the double-crystal γ-spectrometer GAMS5 was finished recently and the instrument is now operational. Measurements with double flat crystals were carried out and we will report here on the progress concerning the characteristics of the spectrometer.     

Synthesis of tritium-labeled 5-fluorouracil and 5-fluorocytosine

The effect of various catalysts and temperature on the solid-phase isotope exchange of 5-fluorouracil and 5-fluorocytosine with tritium was studied. The isotope exchange yielding the desired compounds is accompanied by dehalogenation and hydrogenation of the 5,6-double bond of the pyrimidine ring. Performing the reaction at a temperature below 160°C allowed the process to be carried out selectively, i.e., with the preservation of the functional groups and double bond in the starting compound. The yields of various products formed in the reactions of tritium with the above compounds were estimated. Synthesis conditions were found, and tritium-labeled 5-fluorouracil and 5-fluorocytosine were prepared with the molar radioactivity of 0.45 Ci mmol⁻¹ (16.7 TBq mol⁻¹) and 4.4 Ci mmol⁻¹ (0.16 PBq mol⁻¹), respectively, and with the purity exceeding 98%.     

Thermoluminescence solid-state nanodosimetry--the peak 5A/5 dosemeter

The shape of composite peak 5 in the glow curve of LiF:Mg,Ti (TLD-100) following (90)Sr/(90)Y beta irradiation, previously demonstrated to be dependent on the cooling rate used in the 400°C pre-irradiation anneal, is shown to be dependent on ionisation density in both naturally cooled and slow-cooled samples. Following heavy-charged particle high-ionisation density (HID) irradiation, the temperature of composite peak 5 decreases by ～5°C and the peak becomes broader. This behaviour is attributed to an increase in the relative intensity of peak 5a (a low-temperature satellite of peak 5). The relative intensity of peak 5a is estimated using a computerised glow curve deconvolution code based on first-order kinetics. The analysis uses kinetic parameters for peaks 4 and 5 determined from ancillary measurements resulting in nearly 'single-glow peak' curves for both the peaks. In the slow-cooled samples, owing to the increased relative intensity of peak 5a compared with the naturally cooled samples, the precision of the measurement of the 5a/5 intensity ratio is found to be ～15% (1 SD) compared with ～25% for the naturally cooled samples. The ratio of peak 5a/5 in the slow-cooled samples is found to increase systematically and gradually through a variety of radiation fields from a minimum value of 0.13±0.02 for (90)Sr/(90)Y low-ionisation density irradiations to a maximum value of ～0.8 for 20 MeV Cu and I ion HID irradiations. Irradiation by low-energy electrons of energy 0.1-1.5 keV results in values between 1.27 and 0.95, respectively. The increasing values of the ratio of peak 5a/5 with increasing ionisation density demonstrate the viability of the concept of the peak 5a/5 nanodosemeter and its potential in the measurement of average ionisation density in a 'nanoscopic' mass containing the trapping centre/luminescent centre spatially correlated molecule giving rise to composite peak 5.     

Characterization of coprecipitated ferroelectric Bi2 VO5·5

Fine powders of orthorhombic bismuth vanadate (Bi₂ VO_5·5) have been synthesized by coprecipitation method. Powder X-ray diffraction and electron microscopic techniques have been used to characterize these samples. The formation of the monophasic Bi₂ VO_5·5 was confirmed. The compacted powders sintered at 1070K have been characterized for their dielectric properties as a function of both temperature (300–900 K) and frequency (100 Hz–10 MHz) and found to be superior to those obtained by the conventional solid-state reaction route.     

DFT方法对LaNi5及LaNi5H0.5晶体结构的预测

根据密度泛函理论,以扩展平面波函数为基集,采用超软赝势技术,对LaNi5 储氢合金及其吸氢后的晶胞模型进行了优化,从理论上给出了其结构参数及性质。计算结果表明该方法能较好地符合 LaNi5 及其氢化物结构的实验值,为该类合金的结构预测提供了一个理论估算途径。此外,根据模型的结构参数分析了LaNi5 中不同间隙位的吸氢稳定性,解释了影响间隙位稳定性的因素。     

Fe_(72.5)Cu_1Nb_(1.5)Mo_(1.5)V_1Si_(13.5)B_9合金的磁性和晶化过程

本文研究了Ｆｅ７２．５Ｃｕ１Ｎｂ１．５Ｍｏ１．５Ｖ１Ｓｉ１３．５Ｂ９合金在不同热处理温度下磁性能的变化及其晶化过程。在ＦｅＣｕＮｂＳｉＢ合金中用Ｍｏ,Ｖ部分替代Ｎｂ仍能获得软磁性能良好的纳米微晶。其最合适的热处理退火条件为５３５℃,保温１小时。与用机械合金法合成纳米晶相比较,佐证了非晶晶化法形成纳米微晶,其优异的磁性能是由于微晶中同时存在晶粒和晶界两种磁相,晶粒与晶界之间有交换相互作用。     

Evolution of the structure of Ti-5Al-5Mo-5V alloy deformed by high pressure

Specific features of straining of the Ti-5Al-5Mo-5V (VT22) alloy deformed by high pressure (cold and hot screw extrusion) are studied depending on its phase composition by the methods of X-ray diffraction analysis, optical microscopy, and electron microscopy. It is shown that the application of high pressure and complex schemes of deformation in combination with the action of temperature enables one to attain high levels of strains in the material without fracture. Under these conditions, new structures (containing nanosized particles responsible for the new properties) are formed. The mechanisms of deformation on the mesolevel are specified. It is shown that, in the process of cold hydroextrusion, the alloy in the one-phase β-state is deformed according to the mechanism of rotation via the formation of strain-induced martensite, whereas the alloy in the two-phase state is deformed according to the mechanism of bending. It is also shown that the mechanisms of deformation strongly depend on the initial phase composition of the alloy. The procedure of hot screw extrusion is characterized by the action of several mechanisms of deformation. Knowing these mechanisms, it is possible to choose the required modes of treatment and obtain structures guaranteeing the optimal combination of strength and plasticity. __________ Translated From Fizyko-Khimichna Mekhanika Materialiv, Vol. 42, No. 3, Pp. 57–64, May–June, 2006.