两性型高分子絮凝脱色剂PAM/AMPS/DMDAAC的合成与表征

以非离子单体丙烯酰胺(AM)、阴离子单体2-丙烯酰胺基-2-甲基丙磺酸(AMPS)和阳离子单体二甲基二烯丙基氯化铵(DMDAAC)为原料,以过硫酸铵、亚硫酸钠、2,2'-偶氮二异丁基脒二盐酸盐为引发荆,合成了絮凝剂产品PAM/AMPS/DMDAAC.在单体质量分数为10%的条件下,得到了最佳的合成工艺为:m(AM):m(DMDAAC):m(AMPS)=7:2:1,反应温度为45℃,偶氮引发剂2,2'-偶氮二异丁基脒二盐酸盐用量为溶液质量分数的0.006%,过硫酸铵用量为溶液质量分数的0.004%,哑硫酸氢钠用量为溶液质量分数的0.002%;对PAM/AMPS/DMDAAC的结构进行红外光谱和透射电镜表征,表明PAM/AMPS/DMDAAC链节上含有季铵盐和磺酸盐基团,分子呈现长链结构,分子链刚性好,交联现象少.     

泥页岩抑制剂ADAN的合成及评价

以丙烯酰胺(AM)为主体,与阳离子单体二甲基二烯丙基氯化铵(DMDAAC)及2-甲基-2-丙烯酰胺基丙磺酸(AMPS)、N-乙烯基吡咯烷酮(NVP)反应,合成了一种两性离子泥页岩抑制剂ADAN,并对其进行了性能评价。结果表明,合成实验最佳条件为:4种单体AMPS、DMDAAC、AM、NVP质量比为2∶1∶6∶1,单体浓度为15%,引发剂浓度0.05%,反应温度50℃。在此条件下,合成产品ADAN不仅具有较强的抑制性,还具有良好的抗温、抗盐和降失水性能。     

两性高分子絮凝剂的合成与应用研究

在氧化还原体系过硫酸铵/亚硫酸氢钠作引发剂条件下,丙烯酰胺(AM)、二甲基二烯丙基氯化铵(DMDAAC)、丙烯酸(AA)经水溶液共聚合成两性高分子絮凝剂PDAA。探讨了单体浓度、反应温度、引发剂用量等因素对聚合反应速率和产物特性黏数的影响。并以硅藻土模拟废水对制得的产品进行了絮凝实验。实验结果表明:合成两性高分子絮凝剂PDAA的较佳条件为:单体质量分数为35%,引发剂用量占单体质量分数为0.1%,反应温度为30℃。     

一种钻井液降滤失剂的合成与室内评价

以丙烯酰胺(AM)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、二甲基二烯丙基氯化铵(DMDAAC)、丙烯基吡咯烷酮(NVP)为单体,亚硫氢酸钠-过硫酸铵(质量比为1∶2)为引发剂,制备了丙烯酰胺-2-丙烯酰胺基-2-甲基丙磺酸钾-二甲基二烯丙基氯化铵-丙烯基吡咯烷酮共聚物(PAADN)。得到的最优合成条件为:m(AM)∶m(AMPS)∶m(DMDAAC)∶m(NVP)=51∶40∶3∶6,总单体质量分数为20%,反应温度为55℃,p H=7,引发剂用量为单体质量的0.5%,反应时间为5 h。并对该聚合物进行红外和热稳定性测试。红外光谱图中未显示双键特征峰,并且含有各个单体特征官能团峰,证明单体全部参与反应;热重-热差分析结果显示,该聚合物初始热分解温度为326.5℃;该降滤失剂对淡水、盐水、人工模拟海水基浆均表现出良好的降失水效果。     

AM/AMPS共聚物的合成与耐温抗盐性能研究

以丙烯酰胺(AM)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为单体,采用氧化还原引发体系在水溶液中合成二元共聚物。结果表明:采用(NH4)2S2O8/NaHSO2CH2OH引发剂,AMPS与AM单体总质量分数25%,二者质量比3∶7,引发剂占单体总量的质量分数0.09%,其中氧化剂与还原剂质量比4∶1,pH=6,反应温度20℃时,AM/AMPS共聚物表观黏度最高,与工业部分水解聚丙烯酰胺(HPAM,3 500万)相比具有更好的耐温抗盐性能。     

疏水缔合阳离子型絮凝剂的合成及其除油性能研究

以丙烯酰胺(AM)、二甲基二烯丙基氯化铵(DMDAAC)和丙烯酸十八酯(OA)为原料，以K₂S₂O₈-Na₂SO₃组成的氧化还原体系为引发剂，通过水溶液聚合法合成一种疏水缔合阳离子型絮凝剂(PADO),并利用红外光谱(FT-IR)、核磁共振氢谱(¹HNMR)和热重(TGA)对其结构进行表征。将PADO用于处理含油废水，考察了单体n(AM)∶n(DMDAAC)、疏水单体OA质量分数、反应温度、反应时间、PADO投加质量浓度对除油效果的影响。结果表明，在反应温度为70℃、反应时间为6 h、n(AM)∶n(DMDAAC)=2∶1、疏水单体OA质量分数为2%、PADO投加质量浓度为40 mg/L的条件下，除油率和浊度的去除率分别可达98.06%和98.53%,破乳絮凝效果良好。含油废水处理后的油质量浓度降至4.36 mg/L,小于国家排放和行业回注标准中的5 mg/L。     

高吸水性树脂PAMA的超声制备与性能研究

超声辐射下,以丙烯酰胺(AM)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为原料,N,N-亚甲基双丙烯酰胺(NMBA)为交联剂,合成AM/ AMPS(PAMA)共聚高吸水性树脂.结果表明:单体中AM的质量分数25%、反应体系pH值为2.0、反应温度为45 ℃和交联剂的质量分数为0.01%时,PAMA共聚高吸水性树脂的吸...     

复合引发体系制备磺化聚丙烯酰胺的研究

以2-丙烯酰胺基-2-甲基丙磺酸（AMPS）和丙烯酰胺（AM）为原料,采用复合引发体系和绝热聚合相结合的方法在水溶液体系中合成磺化聚丙烯酰胺（SPAM）,考察了单体质量分数、引发剂质量分数、单体配比、引发剂配比、pH值、聚合起始反应温度对聚合反应的影响。确定SPAM的最佳合成条件为：单体质量分数10％、引发剂质量分数0,15％、AMPS与AM质量比1．0：1、偶氮二异丁腈（AIBN）与氧化还原引发剂质量比4：1、pH值6、聚合起始反应温度40℃,在此条件下,制得的SPAM的分子量为6．13×10^6,其耐温抗盐性能明显优于采用单-氧化还原引发剂制备的SPAM及工业部分水解聚丙烯酰胺（分子量7×10^6）。     

疏水缔合压裂液用稠化剂HAP-1的制备及性能评价

以功能疏水单体N-十二烷基丙烯酰胺(N-DAM)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酰胺(AM)和丙烯酸(AA)为原料,采用水溶液法制得疏水缔合压裂液用稠化剂(HAP-1),考察了合成过程中不同因素对HAP-1性能的影响,确定了HAP-1的最佳合成工艺:反应时间为4 h,反应温度为70℃,单体总质量分数为25%,引发剂质量分数为0.03%(相对于单体总质量),反应体系p H为8,单体摩尔比n(AM)∶n(AA)∶n(AMPS)∶n(N-DAM)=80∶15∶4∶1。性能评价结果表明,HAP-1压裂液具有良好的耐温性能、抗剪切性能、悬砂性能和破胶性能,且破胶液残渣质量浓度低于常规压裂液破胶液,适于90℃以下油气储层压裂改造。     

三元驱油用磺化聚丙烯酰胺的合成与性能研究

以丙烯酰胺(AM)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)和苯乙烯磺酸钠(SSS)为原料,采用氧化还原和偶氮复合引发体系,在水溶液中进行自由基聚合反应,制得磺化聚丙烯酰胺(SPAM)即三元共聚物AM/AMPS/SSS。结果表明:SPAM最佳合成条件为单体质量分数10%,SSS质量分数0.5%,引发剂质量分数0.06%,氧化还原引发剂与偶氮引发剂质量比为1∶4,pH值为9,聚合起始反应温度5℃,在该条件下制得的SPAM的相对分子质量7.36×106,其耐温抗盐性能明显优于工业部分水解聚丙烯酰胺。     

Compact Swelling in Bi1.4Pb0.6Sr2Ca2Cu3.6Oy During the Formation of High-Tc Superconducting Phase

Compact swelling in Pb-doped Bi-Sr-Ca-Cu-O superconductor has been studied by observing the effects of the size of calcined powders, volatilization of materials, and sintering of high- T _c (2223) powders. The bulk density increases at the early stage of sintering, for about 20 h, and then decreases. Densification occurs when the low- T _c (2212) phase and a liquid phase exist, whereas dedensification occurs with the formation of the 2223 phase regardless of the presence of the liquid. Gas evolution from specimens does not appear to be responsible for compact swelling. Compact swelling is explained by anisotropic growth of thin, platelike 2223 grains in random orientation. When 2223 grains grow in a preferred direction, compact swelling is suppressed.     

Synthetic routes to nanoscale BxCyNz architectures

B_xC_yN_z nanoscale materials, hybrids of h-BN and graphite, have been recently synthesised using various techniques. Here, we present the latest advances in the synthesis and characterisation of B-C-N nanotubes and nanofibres. In particular, we focus on layered BC₂N, BN, BC and CN_x systems, reviewing their production methods as well as their structural and electronic properties. These materials may find important applications in the fabrication of nanotransistors, robust nanocomposites, conducting polymers, storage components and field emission sources.     

(Bi1/2Na1/2)TiO3–Ba(Cu1/2W1/2)O3 Lead-Free Piezoelectric Ceramics

(Bi_1/2Na_1/2)TiO₃ with 0–6 mol% Ba(Cu_1/2W_1/2)O₃ (BNT-BCW), a new member of the BNT-based group, has been prepared following the conventional mixed oxide route. The compacted bodies were sintered at 1130°C for 2 h to get dense ceramics. The addition of BCW into BNT ceramics facilitated the poling process because of a reduction in leakage current. 0.995BNT·0.005BCW ceramics exhibit a relatively high piezoelectric constant ( d ₃₃= 80 × 10⁻¹² C/N) and a relatively low dielectric loss (tan δ= 1.5%). Increased amount of BCW was found to increase the dielectric constant and loss of BNT-BCW ceramics and to suppress the grain growth. During sintering, some BCW diffuses into the lattice of BNT to form a solid solution and some remains on the grain boundaries.     

Structure Evolution from Pb(Mg1/3Nb2/3)O3 to La(Mg2/3Nb1/3)O3

The crystal structure of lanthanum-modified lead magnesium niobates having composition (Pb_{1− x} La _x ) (Mg_{(1+ x )/3}-Nb_{(2− x )/3})O₃ with X = 0 to 1 was investigated by X-ray powder diffraction. It was found that the fundamental reflections from perovskite structure remain in the whole range of composition. The superlattice reflections from the A(B'_1/2-B"_1/2)O₃ ordered structure are also well preserved for La content greater than 50 at.%; however, a series of extra peaks of mixing indices appears, with intensities gradually enhanced with the increase of La content. For the complete substitution of Pb by La, a splitting of some reflections can be observed in the diffraction pattern. The results indicate that the crystal structure evolves continuously with the La content, from disordered cubic perovskite of space group Pm 3 m for X = 0, to ordered cubic perovskite of space group Fm 3 m for X = 0.5, distorted cubic perovskite of space group Pa 3 for 0.5 < X < 0.9, and finally to a rhombohedral perovskite, possibly belonging to the space group R 3 , for X ≥ 0.9. In the evolution of structure, a linear reduction of the lattice constant of the perovskite cell from 4.048 to 3.964 Å was observed.     

炭黑/煤矸石/碳纳米管复合填料体系对天然橡胶性能的影响研究*

利用硝酸氧化法对碳纳米管(CNTs)进行纯化,并用环氧天然橡胶(ENR)进行改性处理。结合胶质量分数测定结果表明, ENR用量15%(质量)时效果最佳。采用胶乳凝聚法制备CNTs/天然橡胶(NR)母料。煤矸石粉(CG)经高温煅烧和表面改性处理。 将CNTs/天然橡胶(NR)母料、CG和炭黑(CB)通过机械混炼法与天然橡胶及配合剂混合,制备CB/CG/CNTs/NR复合材料,并对复合材料进行硫化特性及物理机械性能。结果表明： CNTs延迟硫化效应明显;相比炭黑,CG对硫化具有促进作用。硫化特性和甲苯溶胀法测定结果表明,在填料份数相同的条件下,单独由CB填充的NR有最大的交联密度,CNTs对交联密度影响不明显。物理机械性能测试结果表明,当CG：CB：CNTs=17.5:16.5:1(Phr)时,NR硫化胶的300%定伸应力和扯断伸长率明显高于单独由CB填充NR,而拉伸强度与之接近,复合填料样填充NR具有较好的综合性能。扫描电镜测试结果表明,复合填料在NR基体中分布均匀。     

Dielectric-State Analysis in Solid-Solution Pb(Yb1/2Ta1/2)O3–Pb(Lu1/2Nb1/2)O3

The structure and temperature dependence of complex lead perovskite dielectrics were investigated for the system (1 − x )Pb(Yb_1/2Ta_1/2)O₃– x Pb(Lu_1/2Nb_1/2)O₃. Superlattice reflections for the compositions 0.8 < x < 1.0 were observed by X-ray diffractometry, and the temperature-composition dielectric-state diagram was determined. In the present study, the disordered middle composition, with 0.2 < x < 0.8, showed a diffuse paraelectric–ferroelectric phase transition, whereas the ordered end compositions, with 0 ≤ x < 0.2 and 0.8 < x ≤ 1.0, revealed successive sharp paraelectric–antiferroelectric and weak antiferroelectric–ferroelectric phase transitions. The dielectric state was confirmed by examining the variation of polarization ( P ) with electric field ( E ).