反相悬浮聚合法AA-AM吸水树脂的研究

采用反相悬浮聚合法,以丙烯酸和丙烯酰胺为主要原料,司班60等作为分散剂,环己烷为介质,过硫酸钾-亚硫酸氢钠为引发剂,N,N’-亚甲基双丙烯酰胺为交联剂,合成吸水树脂;考察了防粘剂、分散剂对树脂性能的影响,并对树脂的各种性能进行了分析。实验表明:丙烯酸和丙烯酰胺的单体摩尔比为1∶1.5,水油比为1∶4,引发剂0.7%(质量分数),交联剂0.06%(质量分数),分散稳定剂8%(质量分数),防粘剂PEG-2000和PEG-6000比为1∶1,丙烯酸与氢氧化钠的中和度为75%,反应温度控制在60℃,反应时间为1.5 h,在此条件下,树脂吸水率达870g/g。     

多元醇为交联剂制备AA/AMPS耐盐性高吸水性树脂

以丙烯酸(AA)和2-丙烯酰胺-2-甲基丙磺酸(AMPS)为单体,环己烷为油相,过硫酸铵为引发剂,采用反相悬浮聚合法制备耐盐性高吸水树脂。研究了单体物料比,交联剂种类及用量,水油比以及不同分散剂种类及配比对吸水树脂吸水率及耐盐率的影响,并通过扫描电子显微镜及傅里叶变换红外光谱对树脂结构进行表征。结果表明:m(AMPS)∶m(AA)为1.0∶10.0,中和度为75%,交联剂甘露醇用量(占单体质量)为6%,水油比为1.0∶3.0,分散剂span60用量(占单体质量)为8.0%,过硫酸铵用量(占单体质量)为0.5%时,制备的耐盐性高吸水树脂的吸水率和吸盐率最高,分别达到1 705,133 m L/g。耐盐性高吸水树脂表面光滑,结构疏松。     

聚乙烯醇丙烯酸接枝共聚制备吸水性树脂的研究

为了开发聚乙烯醇的非纺织领域的应用,试验在水溶液中氮气保护的情况下,以N,N,-亚甲基双丙稀酰胺为交联剂．铈4＋引发聚乙烯醇与丙烯酸接枝共聚制备吸水性树脂。考察了交联剂用量、引发剂用量、单体用量、反应温度、反应时间和丙烯酸中和度对产物吸水率的影响．得到如下最佳反应条件;胶联剂与聚乙烯醇的质量比为0．14;引发剂与聚乙烯醇的摩尔比为0．04;单体丙烯酸与聚乙烯醇的质量比为6;反应温度为50℃;反应时间为5h;丙烯酸中和度为50％。在该条件下制得吸去离子水高达500余倍的吸水性树脂。     

超声辅助下聚丙烯酸/丙烯酰胺高吸水性树脂的合成研究

借助超声波的分散、辅助引发作用,以丙烯酸(AA)和丙烯酰胺(AM)为单体,以N,N’-亚甲基双丙烯酰胺(NMBA)为交联剂,以过硫酸钾(K2S2O8)为引发剂,无氮气保护下,采用超声波细胞粉碎法制备了聚丙烯酸/丙烯酰胺(P(AA-AM))高吸水性树脂。采用正交试验研究了树脂吸水性能最优的反应条件。通过单因素实验,重点考察了反应温度、引发剂用量、单体配比等对树脂吸水率的影响。用红外光谱(FTIR)和扫描电镜(SEM)对树脂的结构与形貌进行表征。结果表明,在超声条件下,可在较短的反应时间内合成高吸水性树脂。最佳工艺条件是AA中和度为70%,T=50℃,n(AM)∶n(AA)=0.3,m(NMBA)∶m(AA+AM)=0.05%,m(K2S2O8)∶m(AA+AM)=0.2%,吸水倍率最高为398.172 g/g。三维网状结构的存在是树脂高吸水性的关键。     

反相乳液聚合制备丙烯酰胺均聚物

采用反相乳液聚合法,以液体石蜡为连续相、丙烯酰胺水溶液为分散相、N,N′-亚甲基双丙烯酰胺为交联剂、过硫酸铵为引发剂、Span-80和OP-10为复合乳化剂,制备了丙烯酰胺均聚物(PAM);考察了溶剂、交联剂及其用量、氮气、单体浓度、乳化剂种类、油水比、引发剂用量对PAM均聚物性能的影响.较佳的聚合条件为:交联剂的用量为单体质量的2.5%,单体AM的含量为40%,油/水质量比接近1.0,引发剂过硫酸铵为单体含量的0.9%,使用复合乳化剂Span-80/OP-10,HLB=5.35.在此聚合条件下,制得的PAM均聚物的粘度较大,稳定性较好.     

聚甲基丙烯酸水凝胶的制备研究

以甲基丙烯酸为原料,N ,N’亚甲基双丙烯酰胺为交联剂,过硫酸钾为引发剂,自由基引发聚合制备聚甲基丙烯酸水凝胶,研究了聚甲基丙烯酸水凝胶的溶胀率、保水率,讨论了交联剂、引发剂的用量以及pH、盐溶液浓度对溶胀性能的影响．实验结果表明：当合成温度为70℃时,p H＝8,盐溶液浓度为0,交联剂、引发剂用量分别为反应物质量的0.6％,1.0％,制备出来的水凝胶的溶胀性能最好．     

多孔P(AAEA-co-DMAA)pH敏感水凝胶的制备

以聚乙二醇(PEG2000)为致孔剂,4-乙酰基丙烯酰乙酸乙酯(AAEA)及N,N’-二甲基丙烯酰胺(DMAA)为单体,制备具有快速响应性的多孔P(AAEA-co-DMAA)pH敏感水凝胶,利用扫描电子显微镜(SEM)表征材料的断面形貌,探讨各制备条件对水凝胶pH敏感性的影响。研究结果表明,PEG2000被洗脱后可在凝胶内部形成互相贯穿的孔洞结构。当n(AAEA)∶n(DMAA)=3∶1,交联剂的质量分数为0.8%,引发剂的质量分数为1.2%,反应温度为68℃,致孔剂质量分数为10%时,多孔水凝胶的pH敏感性最强。     

玉米淀粉/苯乙烯/丙烯酸酯类接枝共聚物的制备与性能

采用乳液聚合法,以玉米淀粉、苯乙烯为原料,考察反应中乳化剂用量、引发剂用量、糊化温度、反应温度、反应时间、淀粉与单体配比、水的用量对接枝率的影响。在这基础上,考察了甲基丙烯酸酯、丙烯酸酯对淀粉/苯乙烯接枝共聚的影响。实验结果表明:引发剂用量0.3 g,乳化剂用量0.35 g,淀粉与单体配比(质量比)1∶4,75℃下预糊化30 min,反应温度65℃,反应时间3.0 h,淀粉/苯乙烯接枝物的接枝率达257.0%;进一步研究接枝物性能,甲基丙烯酸酯优于丙烯酸酯。     

多孔P（AA-co-AM）高吸水性材料的制备

以过硫酸钾为引发剂,N,N＇-亚甲基双丙烯酰胺为交联剂,碳酸钠为发泡剂,十二烷基苯磺酸钠为泡沫稳定剂,丙烯酸（AA）和丙烯酰胺（AM）为单体,采用泡沫体系分散聚合法制备P（AA-co-AM）高吸水性材料,利用红外光谱（FTIR）及扫描电子显微镜（SEM）对材料的结构进行表征并探讨材料的最佳制备条件。FTIR及SEM结果表明通过此方法可成功制得P（AA-co-AM）多孔高吸水性材料,较优制备条件为n（AM）：n（AA）=0.3,n（Na2CO3）：n（AA）=0.5,引发剂占单体质量比为0.5%,交联剂占单体质量比为0.07%,泡沫稳定剂占单体质量比为3.5%。材料在生理盐水中的吸液速率快于在蒸馏水中的吸液速率。     

响应面优化香蕉茎纤维-丙烯酰胺高吸水树脂的制备工艺

以香蕉茎纤维和丙烯酰胺为原料,过硫酸钾和亚硫酸钠为引发剂,制备了香蕉茎纤维-丙烯酰胺高吸水树脂.在单因素实验的基础上,以树脂吸水率为响应值,选取酰纤比、反应温度、引发剂用量和交联剂用量为自变量,利用Box-Behnken设计和响应面法对各自变量及其交互作用对树脂吸水率的影响进行了研究,得到了二次多项式回归方程模型.香蕉茎纤维-丙烯酰胺高吸水树脂的最佳制备工艺条件为:酰纤比9.9 g/g、反应温度48℃、引发剂用量1.9%和交联剂用量0.18%.在此条件下,测得所制备的吸水树脂吸水率为461.22 g/g,与预测值相对误差为0.68%,说明响应面优化香蕉茎纤维-丙烯酰胺高吸水树脂的制备工艺具有较高的准确性与可靠性,该方法可用于香蕉茎纤维-丙烯酰胺高吸水树脂制备工艺的优化.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…