明胶-丙烯酰胺接枝物对胶片照相性能的影响

利用凝胶层析法作为明胶接枝丙烯酰胺产物的分析手段,研究了不同分子量及其分布、不同粘度的产物对胶片照相性能的影响,发现该接枝产物对胶片有明显的增黑效果。     

明胶接枝共聚丙烯酸铵-丙烯酰胺

研究了溶液聚合法制备明胶-聚(丙烯酸铵-丙烯酰胺)(G-g-PAA/PAM)可降解高吸水性树脂的方法.对明胶/单体及丙烯酸铵/丙烯酰胺质量比、丙烯酸中和度、单体浓度及N,N'-亚甲基双丙烯酰胺和过硫酸钾相对含量影响产品吸(盐)水性能的情况进行测试,从中优选出较合适的反应条件,并用红外光谱对产物进行表征.该高吸水性树脂的吸水倍率达1187g/g,吸盐水倍率选82g/g.FTIR分析表明,反应产物为明胶与丙烯铵、丙烯酰胺的接枝共聚物.     

氯化聚乙烯对氯丁橡胶与甲基丙烯酸甲酯接枝共聚反应的影响

研究了高氯氯化聚乙烯(HCPE)对氯丁橡胶与甲基丙烯酸甲酯接枝共聚及其反应产物的影响。结果表明,HCPE能加快聚合速率,提高转化率、接枝效率和接枝度。含HCPE的产物,含有较高分子量的级份,分子量分布较宽,树脂相的分布比较均匀,并具有较好的机械性能和较高的粘接强度。     

氨基酸改性支链淀粉/丙烯酰胺共聚物的制备及其抑菌性的研究

以玉米支链淀粉、丙烯酰胺为原料,合成了淀粉接枝丙烯酰胺共聚物.利用氨基酸对淀粉接枝丙烯酰胺共聚物进行了改性,并对反应条件进行了研究,得出了最佳条件为:pH值为11,反应温度70℃下反应10h,最佳条件下氨基酸转化率为24.2%.对改性产物通过菌落计数法进行抑菌实验,实验表明该产物具有一定抑菌效果.     

明胶-甲基丙烯酸甲酯接枝共聚物的溶胀性能

以明胶(Gel)和甲基丙烯酸甲酯(MMA)为原料,制备了明胶-甲基丙烯酸甲酯接枝共聚物.分别考察了单体浓度、引发剂用量、反应时间、反应温度及与蒙脱土(MMT)插层复合对接枝反应产物溶胀性能的影响,确定了最佳制备条件.结果表明,接枝共聚及与MMT插层复合可以显著降低明胶的溶胀度.     

接枝交联明胶的研究(Ⅱ) 具有亲水性与亲油性接枝支链的交联明胶的合成和表征

首次以ＡＰＳ－Ｎａ２Ｓ２Ｏ３为引发体系，实现了甲基丙烯酸甲酯（ＭＭＡ）与Ｇｅｌｘ－ｇ－ＰＭＡＡ的接枝共聚反应，研究了反应规律；以ＩＲ表征了产物的结构；得到两亲性接枝共聚交联明胶，并对此类接枝改性明胶在各种溶剂中的溶胀行为作了初步的研究。     

CuX/bpy催化体系中聚氧乙烯大单体与甲基丙烯酸甲酯接枝共聚物的合成与表征

以正丁基溴为引发剂，卤化亚铜／联吡啶(bpy)为催化剂，研究了甲基丙烯酸甲酯（MMA）与末端为丙烯酰胺基的聚氧化乙烯（PEO）大单体的原子转移自由基聚合（AWTRP）反应，得到的实测分子量与理论分子量相近，分子量分布较窄，有预期结构的接枝共聚物，用IR，^1H-NMR,VPO,GPC,DSC等进行表征，并对单体总浓度，投料比，引发剂及反应时间对共聚物的组成和分子量的影响进行了讨论。     

用焦磷酸络锰(Ⅲ)引发丙烯酰胺接枝魔芋粉合成增稠剂

用焦磷酸络锰的三价离子Mn^3 为引发剂，引发魔芋粉（KGM）与丙烯酰胺（AM）的接枝共聚。研究了引发剂浓度、单体浓度、pH值、反应温度、反应时间、反应介质以及KGM预处理方式等对接枝反应的影响，同时，还研究了产物的水溶性及增稠性。     

离子液体中均相制备纤维素/AM/BMA接枝共聚物的研究

以离子液体为反应介质,纤维素为基体,丙烯酰胺、甲基丙烯酸丁酯为接枝单体,过硫酸钾为引发剂,N,N’-亚甲基双丙烯酰胺为交联剂,通过自由基聚合法制备出了纤维素/丙烯酰胺/甲基丙烯酸丁酯接枝共聚物。通过正交试验,确定了接枝共聚物的最佳合成条件,在此条件下制备的接枝产物,接枝率为89%,接枝效率为38%,吸水倍率为560g/g。利用红外光谱(FT-IR)、X射线衍射(XRD)、热分析(TG/DTA)和扫描电镜(SEM)对接枝产物进行了结构表征。     

(NH_4)_2S_2O_8-CO(NH_2)_2引发丙烯酸甲酯与明胶接枝共聚

研究了(NH_4)_2S_2O_8-CO(NH_2)_2新氧化还原体系引发丙烯酸甲酯、明胶接枝共聚,讨论了各反应参数如聚合温度、引发剂浓度、单体浓度、主链浓度及反应时间对接枝率、接枝效率、总转化率的影响。测定了接枝聚合物粘度及支链分子量。     

Evaluation of Hardening Using the Sol Fraction of Gelatin Films (Review)

The low molecular weight component of gelatin has been investigated by determination of the molecular weight distribution of the sol fraction from hardened gelatin films. The hardeners used were formaldehyde and mucochloric acid. Different hardening conditions and gelatin types were studied. It was observed that a couple of weeks were needed to reach a stable level of hardening. Acid- processed gelatins exhibited higher reactivity than lime-processed gelatins. The results indicate that the method seems to be effective as an evaluation of gelatin hardening.     

The Structure of Gelatin Crosslinked with Formaldehyde

Crosslinking a gelatin layer with formaldehyde gives a decrease in swelling and solubility as function of the reaction time and the pH value. The molecular weight distribution of the crosslinked gelatin is determined by gelchromatography, the average molecular weight by sedimentation in the ultracentrifuge and the helical content by means of circular dichroism. In the reaction process, the average molecular weight M_w as well as the amount of gelatin molecules with M ≤ 10.10⁶ increase, while the material of M ≈ 10⁵ decreases. The formation of helix is hindered by crosslinking with formaldehyde. The cross-linking in solution is intercatenar as well as intracatenar.     

水相沉淀法制备丙烯腈-丙烯酰胺共聚物及其结构研究

以丙烯酰胺(AM)为共聚单体,采用水相沉淀法制备了丙烯腈/丙烯酰胺共聚物。研究了AM对聚合反应以及共聚物结构的影响。结果表明,AM竞聚率高于AN,倾向于均聚反应,会降低PAN的分子量,提高聚合反应的转化率;少量AM会略微改变分子链中的立构规整度,提高PAN的结晶度,降低晶粒尺寸。     

Preparative Chromatography and Analysis of Molecular Weight Fractions of Gelatin

Preparative scale gel filtration chromatography has been used to isolate different molecular weight fractions of gelatin for subsequent chemical analysis. The broad molecular weight distribution of gelatin was fractionated into four regions corresponding to high molecular weight, beta, alpha and low molecular weight material. Characterization of the isolated fractions included molecular weight distribution, amino acid composition, total active sulphur measured by cysleic acid analysis after oxidative hydrolysis and analysis of the pyridinoline crosslinks. A limed bovine ossein gelatin was characterized by these ttxhniques.     

Change in the Molecular Weight Distribution of Gelatin by a High Pressure Slurry Jet

Abstract

Physical and photographic properties of gelatin depend on the molecular weight distribution of the gelatin, which it is important to control. We controlled the molecular weight distribution of gelatin by pressurizing the sample gelatin solution and jetting it at high velocity from a nozzle to a collision plate. II was found that this method teas effective in controlling the molecular weight distribution of gelatin and in preparing a gelatin which contains mainly ± and β components and few high and low molecular weight components.     

马来酸酐-丙烯酰胺共聚物的合成及表征

针对溶剂法合成马来酸酐-丙烯酰胺共聚物时聚合物中MA含量少、利用率低以及聚合物收率低的难题,文中在四氢呋喃(THF)中,沉淀聚合合成了马来酸酐-丙烯酰胺(MA-AAM)共聚物,考察了单体投料比、单体总浓度、引发剂用量以及反应时间对共聚的影响.凯式定氮法测定了聚合物中AAM含量,化学计算得到了MA含量.循环利用聚合残液八...     

壳聚糖/阳离子聚丙烯酰胺水分散聚合物的制备

以水溶性壳聚糖(Cts)作为新型分散剂,甲基丙烯酰氧乙基三甲基氯化铵(DMC)和丙烯酰胺(AM)为单体原料,偶氮二异丁基脒二盐酸盐(V-50)为引发剂,采用水分散聚合技术合成了壳聚糖/阳离子聚丙烯酰胺聚合物(Cts/CPAM),探讨了反应条件对聚合物分子量的影响。结果发现,单体质量分数为3.75%~4.25%、AM∶DMC(质量比)为9∶4、分散剂质量分数为1.5%~1.75%、无机盐质量分数为10.0%~17.5%、引发剂质量分数为0.0035%~0.0045%、反应温度为55℃~60℃时,分散聚合体系稳定,所制备聚合物的分子量较高。     

Studies on the Properties of Fractionated Gelatins

Gel permeation chromatography (CPC) and temperature solubility were used to isolate different molecular weight fractions of several photographic gelatins. The dependence of the amino acid composition of impurities and metal ion contents on molecular xveight was investigated. The lower molecular weight fraction had an unusual amino acid composition. The difference in amino acid composition was observed according to the raw material species, the methods of manufacture and those of fractionation. This lower molecular weight fraction contained more tyrosine, histidine, methionine, hydroxylysine and hydrophobic amino acids than the original gelatin, while it contained less lysine, alanine and acidic amino acids than the original gelatin. It was considered that the low molecular weight fraction contained a certain amount of telopeptide, peptide from the a2 (1) chain and non- collagenous proteins. High contents of iron and calcium ions as impurities were observed in higher and lower molecular weight fractions.     

淀粉与DADMAC-AM接枝共聚反相胶乳

以淀粉、丙烯酰胺（ Ａ Ｍ）、二烯丙基二甲基氯化铵（ Ｄ Ａ Ｄ Ｍ Ａ Ｃ）为原料,采用氧化还原引发体系,通过反相乳液聚合技术,合成接枝共聚物。讨论了合成条件对产品性能的影响及在造纸中的应用。结果表明,改变投料方式、控制两种单体适当的配比,可以获得较高分子量和阳离子度的稳定胶乳产品。通过造纸滤水性试验发现,当将本品用量为 ０．０５％ 加入造纸系统,填料留着率与目前普遍采用的两种试剂——阳离子淀粉和阳离子聚丙烯酰胺相比,数值都高。因此,它是造纸业很好的助留助滤剂。