Synthesis of Vinyl Polymer-Starch Composites to Serve as Size Base Materials

Starch was polymerized independently with acrylamide, acrylic acid, methacrylic acid and acrylonitrile (AN) using potassium persulphate (K₂S₂O₈) as initiator. The products of the polymerization reaction consisted of free starch, grafted starch, homopolymer and oxidized starch. The ratios of these composite constituents were found to differ considerably depending upon the nature of monomer as evidenced by differences in viscosity curves (amylograph-viscograph) as well as sizeability of the composites and their ease of removal from cotton yarns during desizing. Also studied was the dependence of the extent of polymerization (grafting and homopolymerization) of AN to starch on K₂S₂O₈ and AN concentrations, polymerization temperature, starch/AN ratio and starch + AN/liquor ratio; and the onset of these factors on the apparent viscosity of the composite obtained thereof. Results indicated that the extent of polymerisation increased by increasing the persulphate concentration to 6 g K₂S₂O₈/100 g starch then levelled off; the same held good for apparent viscosity but the latter decreased upon using concentrations higher than 6 g K₂S₂O₈/100 g starch. While the extent of polymerization increased over a range of 8-32g AN/100 g starch, apparent viscosity decreased. Raising the polymerization temperature from 30 to 60°C caused significant enhancement in the extent of polymerization but with the certainty that maximum apparent viscosity was attained at 50°C. The extent of polymerization was much favoured at higher AN ratio, but maximum apparent viscosity was attained at starch/AN ratio of 83:17. On the other hand, the extent of polymerization decreased by increasing starch + AN/liquor ratio upto 1:75 then remained almost constant upto a ratio of 1:12.5; meanwhile maximum apparent viscosity was observed at a material/liquor ratio of 1:7.5. The results were interpreted in terms of differences in the magnitude of constituents of the poly (AN) - starch composite and their affinity for and swellability in water.     

Graft Polymerization of Acrylamide onto Starch Using Ferrous-Starch Thiocarbonate-Persulphate Redox System

Graft copolymerization of acrylamide (Aam) onto starch using ferrous-starch thiocarbonate-persulphate redox system was investigated under different conditions including alkali concentration in the precarbon disulphide treatment, potassium persulphate concentration, ferrous ion concentration, monomer concentration, pH of the polymerization medium, polymerization temperature, use of solvent/water mixture instead of aqueous medium, and liquor ratio. The role of thiocarbonation on the magnitude of grafting of acrylamide onto starch has been studied with respect to K₂S₂O₈ and ferrous ion concentrations. The graft yield was significantly favoured in acidic medium as well as by increasing the persulphate concentration, acrylamide concentration, and polymerization temperature. Carbon tetrachloride constitutes the optimal medium for polymerization. Grafting was also favoured in either higher or lower liquor ratios.     

Synthesis and Properties of Polyacrylamide-Starch Graft Copolymers

Graft polymerization of acrylamide onto rice starch was investigated under different conditions using potassium persulphate, benzoyl peroxide or potassium permanganate as initiator. This has led to establishment of the most appropriate grafting conditions for each of these initiators. Under these conditions grafting was characterized by two rates regardless of the initiator used. The first rate occurred during the initial stages of polymerization while the second during the later stages. The first rates of grafting for the three initiators were very close indicating the insignificant effect of the nature of the initiator on grafting during the initial stages of the reaction. On the other hand, the second rates of grafting exhibited the order: potassium persulphate < benzoyl peroxide < potassium permanganate, reflecting the role played by the nature of initiator during the later stages of the reaction. Substantial differences in solubility were observed between polyacrylamide-starch graft copolymers and unmodified starch as well as among copolymers prepared using the three initiators. Although the copolymers acquired higher solubility percent than the unmodified starch, yet nature of initiator, graft yield, structural changes in the copolymer occuring during grafting and the temperature of solubility measurement determined the solubility percent. Copolymers prepared using benzoyl peroxide or potassium persulphate showed lower viscosity than the unmodified starch. The opposite was the case with respect to copolymer prepared using potassium permanganate.     

衣康酸/丙烯酸与聚酯织物接枝共聚性能

研究了在水溶液中以过氧化苯甲酰为引发剂,衣康酸/丙烯酸为单体与碱处理后的三叶形聚酯(PET)平纹织物接枝共聚;对共聚条件如聚合温度、时间、引发剂浓度、单体物质的量比等进行研究,得出最佳聚合条件。电子扫描电镜照片和傅里叶红外变换光谱显示衣康酸/丙烯酸共聚到聚酯大分子上。研究结果表明随着接枝率的上升,织物吸湿快干性能提高;阳离子染料上染率大幅度提高,织物色光鲜艳。     

Poly(Acrylic Acid)-Starch Composites. A Key for Improving Sizeability and Desizeability of Starch from Cotton Textiles

Maize and rice starches were independently polymerized with acrylic acid (AA) using potassium permanganate/citric acid initiation system. The dependence of total conversion (grafting and homopolymerization) on AA, potassium permanganate and citric acid concentrations, time and temperature of polymerization and rate of stirring were studied. Based on the results appropriate conditions for preparation of poly(AA)-starch composites were established. While the total conversion increased by increasing AA concentration from 10% to 30%, based on weight of starch (ows), maximum total conversion occured upon using 0,2% potassium permanganate along with 0.025% citric acid, ows, for 10 min at 40°C and stirring rate of 300 r. p. m. It was further disclosed that: (a) the total conversion for maize starch is higher than rice starch, (b) the apparent viscosity of the composite increases by increasing AA concentration from 10% to 30% and polymerization temperature from 30°C to 50°C, (c) for 10% AA concentration the composite consists of 97.67 starch and 2.33% poly-(AA) of which 1.36% is grafted whereas for 30% AA concentration the composite consists of 79.3% starch and 20.7% poly(AA) of which 3.2% is grafted, (d) the sizeability of native starches is considerably improved after polymerization with AA and (e) size removal from cotton fabric with the composites to ca. 80% while wize removal from cotton fabric sized with native starches amounts to ca. 20%.     

丙烯酸接枝淀粉的制备及其印花性能

采用丙烯酸(AA)单体对酸解玉米淀粉进行接枝,讨论了丙烯酸单体与玉米淀粉剩基（AGU）配比、丙烯酸单体pH值、引发剂用量、反应时间及温度对接枝产物接枝率、抱水性及PVID值的影响,并用红外光谱（FTIR）对接枝产物进行表征。试验得出丙烯接枝酸解玉米淀粉优化工艺为：n(AA):n(AGU)=2:1,丙烯酸单体pH值为6、引发剂n(H2O2)/n(FeSO4)=1.98,n(H2O2)=0.529mmol,接枝反应温度为50℃及时间为3h。所得接枝产物接枝率为5.14%,羧基含量为4.02%;接枝产物的抱水性为10.5mm,PVID值为0.34,各项性能与海藻酸钠相近,可作印花原糊用。     

反相悬浮法红薯淀粉/丙烯酸接枝反应工艺研究

采用反相悬浮法以淀粉接枝丙烯酸合成吸水性树脂;探讨单体与淀粉质量配比、交联剂、引发剂、油水体积比、单体中和度等因素对树脂吸水率影响,通过单因素和正交实验得到最优工艺条件:单体与淀粉质量配比5∶1、交联剂用量0.122 g、引发剂用量1.3 g、油水体积比1.3∶1、单体中和度70%;聚合物在自来水中最大吸液倍率为95 g/g,且产品具有良好吸水速率。     

糯玉米淀粉高吸水性树脂制备及结构表征

为掌握糯性淀粉高吸水性树脂的制备条件及吸附性能,以糯玉米淀粉为原料,采用水溶液聚合法制备了糯玉米淀粉高吸水性树脂,系统分析了淀粉用量、引发剂用量、交联剂用量、单体中和度、反应温度等因素对树脂吸水倍率的影响,并对其结构进行表征。结果表明,糯玉米淀粉高吸水性树脂的适宜制备条件为:反应温度75℃,以单体质量计,单体与淀粉用量质量比为15∶1,单体丙烯酸中和度为pH4.8,引发剂过硫酸铵用量为0.15%,交联剂丙三醇用量为0.11‰,此时所得树脂的吸水倍率为1 641.78 g.g-1。红外光谱扫描结果表明,糯玉米淀粉与丙烯酸发生了接枝共聚反应。     

双亲两嵌段接枝淀粉浆料的制备及其上浆性能

为提高淀粉浆料的使用性能,为纺织经纱上浆提供新型接枝淀粉浆料品种,以丙烯酸(AA)和丙烯酸丁酯(BA)为接枝单体,2-溴异丁酯化淀粉(BBES)为大分子引发剂,利用电子转移活化再生催化剂原子转移自由基聚合技术成功制备了双亲两嵌段接枝淀粉[BBES-g-(PAA-b-PBA)].以酸解淀粉、BBES为对比样,探讨了双亲两...     

Application of response surface methodology (RSM) for optimization of cassava starch grafted polyDADMAC synthesis for cationic properties

Response surface methodology was used to study the process optimization of cationic percentage through grafting diallyldimethylammonium chloride (DADMAC) into cassava starch. Based on Box–Behken design, quadratic models were developed to correlate the synthesis variables: concentration of DADMAC (A), concentration of initiator (B), and polymerization temperature (C), to the responses of cationic percentage (y). Analysis of variance (ANOVA) revealed that the concentration of initiator was the most significant variable for the response. The optimum preparation conditions for starch grafted polyDADMAC were 14% cationic using 31 g DADMAC/10 g dry starch of concentration DADMAC, a polymerization temperature of 74°C, and 4.92 g cerric ammonium nitrate/10 mL of initiator concentration.     

Grafting of 2‐(Dimethylamino)ethyl Methacrylate onto Potato Starch Using Potassium Permanganate/Sulfuric Acid Initiation System

Graft copolymerization of 2‐(dimethylamino)ethyl methacrylate onto potato starch was carried out in an aqueous medium using a potassium permanganate/sulfuric acid initiation system. The grafting percentage and grafting efficiency were determined as functions of the concentrations of potassium permanganate, sulfuric acid and the monomer, and also polymerization temperature and time. The IR spectrum of the graft copolymer showed the peaks characteristic of the grafted chains. The grafting percentage and grafting efficiency increased and then decreased with increasing the concentrations of potassium permanganate, sulfuric acid, and the monomer, as well as polymerization temperature. The grafting reaction was characterized by an initial fast rate followed a lower rate which leveled off after a certain time. The overall activation energy for the grafting was estimated to be 66.9 kJ/mol.     

马铃薯淀粉与醋酸乙烯酯接枝聚合影响因素的研究

以马铃薯淀粉为接枝骨架,过硫酸铵为引发剂,醋酸乙烯酯(VAc)为接枝单体进行接枝共聚。考察了不同引发剂浓度、反应温度、反应时间、单体配比、淀粉浓度对单体转化率、接枝率及接枝效率的影响,确定最佳工艺条件为:引发剂浓度18 mmol/L,反应温度60℃,反应时间3.5 h,单体配比2.5:1,淀粉浓度5%。并通过扫描电镜,X射线衍射,傅里叶红外光谱对淀粉接枝共聚物进行分析,结果表明:淀粉接枝共聚后,淀粉的微观形貌已经改变,结晶度降低且醋酸乙烯酯成功接枝在马铃薯淀粉上。     

Graft Copolymerization Onto Starch. 3: Grafting of Acrylamide Using Ceric Ion Initiation and Preparation of Its Hydrogels

The grafting of acrylamide (AM) onto maize starch in aqueous medium initiated by ceric ammonium nitrate (CAN) has been studied gravimetrically under nitrogen atmosphere. The effect of concentration of monomer and initiator, polymerization time and reaction temperature has been studied in terms of efficiency of grafting (%GE) and percentage Add-on (%Add-on). The %GE was found to decrease with increase in monomer concentration, but the reverse trend was obtained on increasing the polymerization time and temperature. The maximum %GE was obtained at 45°C when polymerization was carried out for 180 min using [CAN] = 0.004 mol/L and [AM] = 0.141 mol/L in 100 mL of distilled water with 2 g of starch. These graft copolymers were characterized by IR spectroscopy and thermogravimetric analysis. The graft copolymers showed enhanced thermal stability than pure starch. Hydrogels were prepared by grafting AM onto gelatinized maize starch followed by saponification of these graft copolymers with NaOH. The maximum water absorption obtained was 170 g/g.     

Tailoring a New Sizing Agent via Structural Modification of Pregelled Starch Molecules Part 1: Carboxymethylation and Grafting

Pregelled starch (PS) was subjected to acid hydrolysis using phosphoric acid to prepare pregelled starches having different molecular sizes. The degraded pregelled starches were carboxymethylated at different reaction times. The carboxymethyl derivatives were grafted with either methacrylamide (MAam) or methacrylonitrile (MAN) as vinyl monomers using ceric ammonium nitrate (CAN) as initiator. Suitability of the new graft derivatives of pregelled starch as sizing agent of cotton yarns was studied. It is shown by the data that the extent of carboxymethylation, expressed as carboxyl content, increases by increasing the extent of hydrolysis and reaction time. Furthermore, the graft yield, expressed as mmol MAam or MAN monomer/100 g graft copolymer (grafted carboxymethylated pregelled starch or grafted carboxymethylated hydrolyzed pregelled starch) increases with increasing extent of carboxymethylation and degree of hydrolysis and follows the order: MAam > MAN. In addition cotton yarns sized with grafted carboxymethylated hydrolyzed pregelled starch – irrespective of the grafting monomer used – have better mechanical properties (tensile strength, elongation at break, and abrasion resistance) than hydrolyzed pregelled starches, carboxymethylated pregelled starch and carboxymethylated hydrolyzed pregelled starches.     

A Novel Copolymer: Starch‐g‐Polyvinylpyrrolidone

In this study, graft copolymerization of N‐vinylpyrrolidone (N‐VP) onto starch was carried out in an aqueous medium using azobisisobutyronitrile (AIBN) as initiator. The variables affecting the graft copolymerization, such as monomer and initiator concentrations, reaction time and temperature, were thoroughly examined. In general, grafting of N‐vinylpyrrolidone onto starch increased with the increase in time and monomer concentration up to a certain value and then leveled off. Similarly, increase both in initiator concentration and temperature first favored and than impeded the grafting reaction. Optimum conditions established for grafting were as follows: N‐VP = 0.7 M, AIBN = 1.5×10^‐3 M, T = 70°C and t = 5 h. Structural changes of the grafted starch were followed by FTIR, intrinsic viscosity and water absorption capacity studies.     

OCC纸浆纤维与己内酰胺接枝改性研究

探讨了碱性环境中OCC纸浆纤维素与己内酰胺在过硫酸钾-亚硫酸氢钠引发体系中进行接枝共聚反应的主要工艺参数。研究结果表明：当单体与浆的质量比为0.5,引发剂过硫酸钾的用量为8.0%（对绝干纸浆）,过硫酸钾和亚硫酸氢钠的质量比为5∶4,反应时间为2.5h,反应温度为60℃时,单体接枝率可达到25.6%,接枝后纤维成纸物理强度性能提高,抗水性增强。用傅立叶红外光谱（FTIR）、X-射线衍射对接枝产物的化学结构进行了表征,结果表明,接枝反应主要发生在纤维的表面和无定形区,对其结晶性没有损害。     

季铵—磺酸型淀粉基高分子聚合物的合成及应用

研究了以淀粉为基材,以丙烯酰胺(AM)、丙烯酰氧乙基三甲基氯化铵(AAC)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为聚合单体,采用溶液聚合技术合成两性接枝共聚物的方法。考察了引发剂用量、反应温度、反应时间、溶解助剂用量、络合剂用量等因素对单体转化率、接枝率、产物特性粘数及溶解性的影响。最佳反应工艺条件为:引发剂质量浓度为0.1%,m(单体)∶m(淀粉)=7∶3,反应温度50℃,反应时间4h。所得产物的接枝率达217.92%、转化率达93.74%、特性粘数达543.31ml/g。该聚合物用于处理油田污水效果好于聚丙烯酰胺类絮凝剂。     

玉米淀粉/丙烯酸在反相乳液体系中接枝共聚反应研究

以玉米淀粉为主要原料,吸水率为指标,利用五因素四水平正交试验对淀粉接枝丙烯酸树脂在反相乳液体系中的接枝反应进行了工艺研究。实验结果表明最佳的反应工艺条件:单体与淀粉质量配比2.5∶1、交联剂用量1.75%、引发剂用量2%、油水体积比1.2∶1、单体中和度50%。聚合物在自来水中最高吸水率为62 g/g,且产品具有良好的保水性。     

Synthesis,Characterization and Properties of Polyacrylamide-Starch Composites

Polyacrylamide-starch composite was prepared by polymerization of maize or rice starch with acrylamide (Aam) using potassium permangante/citric acid initiation system. Major factors affecting the polymerization reaction were studied with a view to discover appropriate conditions for preparation of the composite. Results obtained imply that the total conversion (monomer converted to homopolymer and graft) increases by increasing concentrations of potassium permanganate from 0.5-0.20%, citric acid from 0.1-0.15 and acrylamide from 10-30% ows. Polymerization can easily be carried out at 40°C for 6 min at pH 4 using a material to liquor ratio 1:25 under a stirring rate of 350 rpm. The results further imply (a) that the apparent viscosity of the composite increases by increasing Aam concentration irrespective of the rate of shear, (b) that for 30% Aam concentration the composite consists of 77.7% starch and 22.3% polyacrylamide of which 10.4% are grafted, (c) that the sizeability of polyacrylamide-starch composites is much better than that of native starches, and (d) that the kind of starch not only determines the total conversion but also the composition of the composite.     

Preparation and Aqueous Properties of Starch‐grafted Polyacrylamide Copolymers

In the present work, starch‐grafted polyacrylamide copolymers were prepared and their rheological properties, either in water or in water‐based muds, were investigated. The advantages in using starches as substrates to prepare additives which are suited for improving stability and the rheological properties of water‐based muds, lie in their low cost, and their lower biodegradability than native starches. Thus, various copolymer series were prepared by free‐radically grafting acrylamide (AM) onto starch using ceric ammonium sulphate (CAS) as initiator. It is shown that the intrinsic viscosity and the molecular weight of the grafted starches are controlled by the initiator and monomer concentrations. Furthermore, to predict the behaviour of the samples under oil‐well conditions, the aqueous solution properties of the copolymers such as water solubility, viscosity, shear rate, were determined as function of temperature, salt concentration and type, and aging time. The knowledge of these properties is a prerequisite for the use of the copolymers in drilling fluids. The data indicate that starch‐grafted polyacrylamide copolymers as compared to the non‐modified starch, behave as shear‐thinning, are salt resistant, and their rheological properties are stable with time. The grafted starches as prepared above were also added to water‐based mud and the rheological properties of the resulting muds were determined under oil‐well conditions. Grafted starches, having high AM contents, are more efficient in decreasing the filtrate volume, and increasing the plastic viscosity of the muds, when compared to PAC‐L, a modified cellulosic polymer used in the filtration control of most water‐based muds. Such improvements in the rheological properties of the muds were found to result from the behaviour and/or properties of the grafted starches in water.