Effect of hyperbranched poly(citric polyethylene glycol) with various polyethylene glycol chain lengths on starch plasticization and retrogradation

A series of hyperbranched poly(citric polyethylene glycol) (PCPEG) materials with varied polyethylene glycol (PEG) chain lengths as plasticizers were mixed with maize starch (MS) via cooking and film‐forming. The structure, pasting property, plasticization, aging property, moisture absorption and compatibility of plasticized starches were studied by means of Fourier transform infrared spectroscopy, X‐ray diffraction, rapid viscosity analysis, tension testing, moisture absorption measurements and scanning electron microscopy. Compared with PEG and citric acid, PCPEG was more effective in promoting starch chain movement and inhibiting the retrogradation of starch film. Also, PCPEG/MS had smaller moisture content. The longer the plasticizer chain, the better were the aging resistance and moisture resistance of starch. But with an increase of PEG chain length, mechanical properties of PCPEG/MS deteriorated and the compatibility between PCPEG and MS decreased. The hyperbranched derivative of PEG with longer chain exhibited improved plasticization and compatibility with starch. © 2019 Society of Chemical Industry     

变性淀粉糊粘度的检测方法比较

介绍了变性淀粉糊粘度的几种检测方法,包括涂-4粘度计检测法、旋转粘度计检测法、快速粘度 分析仪检测法、布拉班德粘度测定法。分别对其工作原理,应用范围和优缺点作了阐述,为更好地选择变性淀 粉粘度测量方法奠定了理论基础。     

多功能淀粉基型煤黏结剂的研究与应用

以型煤稳定性为考察指标,研究NaOH与玉米淀粉的反应时间、反应温度、反应物配比及无烟粉煤与黏结剂的比例等因素对型煤稳定性的影响。用改性淀粉黏结剂与无烟粉煤混合,采用单因素实验法优化型煤成型的制备条件。黏结剂的最佳制备条件：反应时间1h,反应温度75℃,淀粉与水的质量比1：14,NaOH与水的质量比1：100,黏结剂占煤球质量的13%。添加了多功能淀粉基黏结剂的型煤的热稳定性较好,采用最佳的制备条件,制得抗压强度为1032.4N的型煤。     

Vinyl-ester-participated transesterification and curing on the physicochemical behavior of Coir-IV

In this article, we report the transesterification of coir with n-Butyl acrylate (BA) and methyl acrylate (MA) under appropriate reaction conditions using NaOH and/or pyridine (Py) as catalyst. The modified vinylog coir was subsequently cured with benzoylperoxide (BPO) in acetone at 50–60°C. The modified fibers were characterized by Fourier transform infrared (FTIR) spectroscopy. Transesterification and curing of transesterified coir lowered the percentage of moisture regain and imparted improved tensile strength and resistance to common chemical reagents. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2283–2291, 1997     

改性淀粉浸润剂的配制工艺及性能分析

介绍了改性淀粉浸润剂的配制工艺,通过检测配制过程中淀粉糊液和淀粉浸润剂的粘度等指标来指导淀粉浸润剂配制工艺参数的设计。分析淀粉糊化程度与油剂乳化过程对淀粉浸润剂性能的影响,使淀粉浸润剂能充分发挥各自组分的优点,生产出优质的玻璃纤维纺织用电子纱。     

淀粉在纺织浆料中的应用

文章简要介绍了淀粉在纺织浆料中的应用概况,介绍丁淀粉浆料的种类及应用,特别强调了变性淀粉的应用情况,同时对纺织浆料今后的发展趋势进行了展望。     

油田用延时性高黏凝胶制备方法研究

基于改性淀粉凝胶于调剖堵水、封堵、钻完井等方面优异的使用性能及应用前景。以淀粉、丙烯酰胺(AM)为原料,偶氮二异丁腈(AIBN)为引发剂,利用淀粉同烯类单体进行接枝共聚,通过交联剂来实现共价键交联,在实验室条件下合成一种适用于中、高温油藏,成胶时间延时至2 h内可控的高强度的改性淀粉凝胶。研究了引发剂的用量、交联剂的用量、反应温度、p H值对胶体成胶性能(体系黏度和成胶时间)的影响。结果表明:在引发剂质量分数介于0.04%~0.06%,交联剂质量分数在5.1%左右,反应温度为80℃,体系p H为10时所制得的聚合物胶体性能最佳,其体系黏度对应为1 950×103 m Pa·s。     

Pozzolanic activity of various siliceous materials

The accelerated pozzolanic activity of various siliceous materials, like silica fume, fly ash (as received and fine ground), quartz, precipitated silica, metakaolin and rice husk ash (RHA; various fineness and carbon content), has been determined. The compressive strength of accelerated tests has been compared with cubes cured in water at 7 and 28 days. Maximum activity has been observed in case of RHA (<45 μ), followed by quartz and silica fume. The 10% replacement of cement by sand has shown accelerated pozzolanic index of 92% compared with 85% required in ASTM for silica fume as mineral admixture.     

Monophosphorylation of cornstarch to improve its sizing properties for heat‐sensitive wool yarns at reduced temperature

Commercial cornstarch was mono‐phosphorylated to different levels of substitution in order to investigate the effect of phosphorylation on the properties of cornstarch for sizing heat‐sensitive wool yarns at reduced temperature. The influences of starch phosphorylation and sizing temperature upon apparent viscosity and viscosity stability of cooked starch paste, starch retrogradation, adhesion to wool fibers, performance of starch film, aerobic biodegradation, mechanical properties, and hairiness of sized wool yarns were evaluated. The phosphorylation level was varied from 0.021 to 0.082 in degree of substitution (DS), while the temperature considered was from 60 to 95°C. It was found that mono‐phosphorylation of starch resulted in enhanced paste stability, reduced retrogradation, strong adhesion to wool fibers, increased performances of starch film, improved mechanical properties of sized wool yarns, and decreased hairiness on surface of sized yarns even if paste temperature was lowered to 60°C. Initially increasing phosphorylation level enhanced positive effects, but excessively increasing the level was not applicable due to marked reduction in tensile strength of starch film. The phosphorylation with a DS value of 0.061 could improve the performances of cornstarch for sizing wool yarns at 60–80°C. Moreover, measurement on BOD₅/COD ratios demonstrated that the phosphorylation did not impede aerobic biodegradation of starch. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

吸湿发热聚丙烯腈纤维的性能研究

采用傅立叶变换红外光谱、扫描电子显微镜、X射线衍射仪和热重分析仪对交联改性制备的吸湿发热聚丙烯腈(PAN)纤维的吸放湿性能进行表征,与普通PAN纤维及进口吸湿发热PAN纤维进行对比。结果表明:交联改性制备的吸湿发热PAN纤维红外光谱出现了较强的羟基峰和羧酸盐的伸缩振动峰,相比普通PAN纤维,表面沟槽加深、粗糙度增加,在100℃内失重率达17.17%,热分解温度提高近70℃,结晶度大幅下降,力学性能降低;交联改性PAN纤维的吸放湿性能较普通PAN纤维大幅度提高,并高于进口吸湿发热PAN纤维,其平衡回潮率约30%,吸湿积分热达155 J/g。     

阳离子淀粉的合成及糊液粘度的研究

合成了离子淀粉并对其糊液粘度进行测定。探讨了阳离子淀粉的糊液粘度与其取代度和性能的相互关系。提出了糊液粘度的测定可作为阳离子淀粉生产控制的一种简便方法。     

Synergetic behavior of low Tg polybutadiene polymers and polysiloxanes as components for glass fiber sizing in composite materials

The effect of low T_g polybutadiene (PBD) rubbery polymer as a part of polysiloxane/PBD E‐glass fibers sizing on mechanical properties of a corresponding epoxy composite material has been evaluated by the punch shear test technique. The results show that the use of hydroxyl terminated PBD led to significant increase in interface shear strength, energy absorption, as well as dynamic modulus and T_g in a corresponding composite material. The sizing composition and fiber morphology were characterized by FTIR spectroscopy and AFM microscopy, respectively. Possible rational for such sizing composition/material property relationship is discussed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Optimizing the mechanical and physical properties of thermoplastic starch via tuning the molecular microstructure through co‐plasticization by sorbitol and glycerol

Nowadays, environmental hazards caused by plastic wastes are a major concern in academia and industry. Utilization of biodegradable polymers derived from renewable sources for replacing common petroleum‐based plastics is a potential solution for reducing the problem. In this regard, starch has become one of the most promising alternatives to non‐biodegradable polymers for depleting plastic waste thanks to its low expense, abundance, renewability and biodegradability. However, the main drawbacks of starch are its poor processability, weak mechanical properties and severe hydrophilicity. In this work, thermoplastic starch (TPS) samples have been prepared using glycerol and sorbitol as co‐plasticizers in a laboratory co‐rotating twin screw extruder. Based on the mechanical test results, glycerol caused higher elongation to break but had lower tensile strength and elastic modulus compared to sorbitol plasticized starch. Fourier transform infrared spectroscopy and DSC results indicated that the hydrogen bond interaction between starch chains and plasticizers could be improved by replacing glycerol by sorbitol, which resulted in higher resistance against retrogradation proved by XRD results. TGA illustrated that the higher the sorbitol to glycerol ratio was, the more stable was the TPS. Using a proper amount of plasticizers (42 wt% total plasticizer, sorbitol to glycerol ratio 2:1) led to the preparation of a TPS sample with optimized properties including enhanced mechanical properties, high thermal stability, strong hydrogen bond formation and high resistance against retrogradation. © 2017 Society of Chemical Industry     

Mass transfer behavior of methane in porous carbon materials

The low mass transfer rate in porous materials hinders the use of adsorbed natural gas as vehicle fuel. Fundamentally, the mass transfer rate depends on the structures of the adsorbents and the operating conditions. Therefore, in this study, the effects of adsorbent (activated carbons) structure and operating conditions on the mass transfer rate of methane (main component of natural gas) were investigated quantitatively, providing a theoretical basis for the synthesis of efficient adsorbent materials. By performing Monte Carlo and molecular dynamics simulations and utilizing a nonequilibrium thermodynamic linearization transfer model, the mass transfer behavior of methane in porous carbon materials was quantitatively evaluated, specifically focusing on the material structure, operating conditions, and feasibility of using natural gas as vehicle fuel. The proposed linear nonequilibrium thermodynamic mass transfer model is applicable to interfacial gas species and provides a valuable tool for gas separation.     

Studies of mechanical and moisture regain properties of methyl methacrylate grafted silk fibers

The mechanical properties such as the tenacity, breaking extension, initial modulus, elastic and work recovery, and stress relaxation behavior of methyl methacrylate (MMA) grafted silk fibers prepared under different conditions were measured and explained in terms of the relative dominance of the stress concentration, reduction in the interchain cohesion, and fiber matrix stiffening at different grafting percentages. The moisture regain characteristics of fibers grafted in the presence of different solvents were also studied and compared. The grafting of MMA on silk was found to improve the recovery properties significantly without affecting the stress relaxation behavior. The moisture regain studies indicate that moisture regain is reduced with increasing length of the grafted poly(MMA) chains. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 969–974, 2002; DOI 10.1002/app.10202     

Comparative investigation of tribological behavior of hybrid dental restorative composite materials

Dental restorative composite materials require appropriate tribological characteristics to bear different stresses in the oral environment. This study inspects the tribological aspects of micro-nano parttticulate filled dental restorative composite materials. Nano-hydroxyapatite (nHA) (0, 2, 4, 6, and 8 wt%), alumina (20 wt%), and titanium oxide (20 wt%) were reinforced in the form of hybrid into the dental resin matrix. The dental resin matrix was fabricated from a base monomer, diluents, initiator, and accelerator. Two body sliding wear tests were conducted by rubbing the prepared nano-composites against a Carbon steel-EN 31 counter plate. ANOVA was used to find significant statistical factors. Besides, the wear mechanisms were clarified via scanning electron microscopy. EDS (energy dispersive spectroscopy) analysis was also done to identify the organic and inorganic groups incorporated in the dental composite samples. The results showed that incorporating high amounts of nHA nanoparticles can improve the wear properties of dental composites. The results of specific wear rate were found significant as per literature.     

Differential scanning calorimetry and wide-angle X-ray scattering studies of bread staling

Wide angle X-ray scattering (WAXS) was used to follow the development of crystal size and strain during the staling of bread containing different additives. In this it was observed that one can classify the good anti-staling additives as gelatin, propylene glycol, maltodextrin and anti-staling enzyme corresponding to the order of increasing crystal size for a particular Bragg reflection in all the samples and correlate using DSC (differential scanning calorimetry) studies of all the bread compositions containing different additives. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1597–1603, 1998     

改性氢氧化铝的制备及其在油相中的粘度行为研究

研究了以硬脂酸、铝酸酯偶联剂改性和烷基酚醛树脂、丁腈橡胶为改性剂经表面原位组合化学方法处理的3种改性氢氧化铝，在液体石蜡和邻苯二甲酸二辛酯中体系粘度随不同改性方法、填充量、温度、烘干和放置时间等因素的变化。研究结果表明，3种改性的氢氧化铝在液体石蜡和邻苯二甲酸二辛酯中均比未改性的具有明显的降粘效果，在邻苯二甲酸二辛酯体系中都具有快速而稳定的抗沉降性。在液体石蜡体系中铝酸酯偶联剂改性的氢氧化铝的降粘效果最好。表面原位组合化学改性的氢氧化铝在邻苯二甲酸二辛酯中的降粘效果最好，且在上述2种体系中抗沉降性最好。它们敞开放置于空气中吸湿后，通过80℃烘干2～4h可恢复改性效果。     

Synthesis and characterization of novel wholly para‐oriented aromatic polyamide‐hydrazides containing sulfone‐ether linkages

Four novel wholly para‐oriented aromatic polyamide‐hydrazides containing flexibilizing sulfone‐ether linkages in their main chains have been synthesized from 4‐amino‐3‐hydroxy benzhydrazide (4A3HBH) with either 4,4′‐sulfonyldibenzoyl chloride (SDBC), 4,4′‐[sulfonylbis(1,4‐phenylene)dioxy]dibenzoyl chloride (SODBC), 4,4′‐[sulfonylbis(2,6‐dimethyl‐1,4‐phenylene)dioxy]dibenzoyl chloride (4MeSODBC), or 4,4′‐(1,4‐phenylenedioxy)dibenzoyl chloride (ODBC) via a low‐temperature solution polycondensation reaction. A polyamide‐hydrazide without the flexibilizing linkages is also investigated for comparison. It was synthesized from 4A3HBH and terephthaloyl chloride (TCl) by the same synthetic route. The intrinsic viscosities of the polymer ranged from 2.85 to 4.83 dL g^?1 in N,N‐dimethyl acetamide (DMAc) at 30°C and decreased with introducing the flexibilizing linkages into the polymer. All the polymers were soluble in DMAc, N,N‐dimethyl formamide (DMF), and N‐methyl‐2‐pyrrolidone (NMP), and their solutions could be cast into films with good mechanical strengths. Further, they exhibited a great affinity to water sorption. Their solubility and hydrophilicity increased remarkably by introducing the flexibilizing linkages. The polymers could be thermally cyclodehydrated into the corresponding poly(1,3,4‐oxadiazolyl‐benzoxazoles) approximately in the region of 295–470°C either in nitrogen or in air atmospheres. The flexibilizing linkages improve the solubility of the resulting poly(1,3,4‐oxadiazolyl‐benzoxazoles) when compared with poly(1,3,4‐oxadiazolyl‐benzoxazoles) free from these linkages. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009