Effect of concentration and pH of solutions on the absorbency of polyacrylate superabsorbents

Polyacrylate superabsorbent (PAS) was synthesized by aqueous solution polymerization crosslinked by N,N‐methylene bisacrylamide. The effect of pH and concentration of several solutions on absorbency (Q) of PAS was studied. The results showed that the absorbency increased at first and then decreased with the increase of the solution's pH; the summit of the absorbing curve was attained when pH was about 6.25. The relation between absorbency and pH could be represented by a quadratic equation and the square difference was relatively small. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 494–499, 2003     

Water absorbency of poly(sodium acrylate) superabsorbents crosslinked with modified poly(ethylene glycol)s

A series of novel crosslinkers, polyethylene glycol diacrylate (PEGDA) with different molecular weights, were prepared, consisting of acryloyl end groups and the PEG backbones. The corresponding poly(sodium acrylate) superabsorbents of 60 mol % neutralization degree were synthesized by using ammonium persulfate and dimethylaminoethyl methacrylate as redox initiators in aqueous solution. PEGDA was characterized by FTIR and ¹H‐NMR. The maximum of water absorbency (Q) of superabsorbents occurred at a specific mole fraction of crosslinker; Q‐values increased with increasing molecular weight of PEGDA at the same mole fraction, whereas the water absorption rate was the opposite, in which Q‐values decreased gradually with time (>24 h). Compared with superabsorbents containing methylene bisacrylamide crosslinker with PEGDA, the Q‐value of the former was significantly less than that of the latter, although levels of the residual monomer and the soluble polymer were opposite. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1851–1856, 2003     

吸水膨胀橡胶的制备及其耐环境性能

以丁腈橡胶和自制的两性共聚吸水树脂为主要原料,以炭黑和白炭黑为补强剂,使用物理共混方法制备出吸水膨胀橡胶,并对其吸水性能,力学性能性能及耐环境性能进行研究.结果表明：当吸水树脂质量份为40 phr,炭黑为20 phr,白炭黑为30 phr时制备的吸水膨胀橡胶的吸水性能和力学性能可达到最佳值,并具有一定的耐高温,耐盐,及耐酸碱腐蚀性能.     

纸张抗透印性与印品阶调层次关系的研究

目的 提出一种控制和预测印品透印质量的评价方法,为印品图文设计及选纸方面提供理论依据,达到经济化、高质量生产的目的。方法 选取5种不同的非涂布纸样,对其紧度、平滑度、油墨吸收性和不透明度指标进行检测,通过建立PTR模型来评价纸样的抗透印性。在这5种纸样印上CMYK阶调色块,即10%~100%（实地）,利用色差法ΔELab来表征每一阶调的透印程度PTq,以ΔELab=3.5作为透印阈值,来建立纸样抗透印性与各阶调之间的关系。结果 从1#纸样到5#纸样的抗透印值PTR依次减小,CMYK在各阶调的透印值也基本呈现相同规律,PTR模型成立;依据透印阈值和每一纸样的线性公式得到相应的阶调值,计算各色的阶调均值,从1#到5#分别为134.15%（计算值）,88.9%,51.95%,42.7%,36.15%,以此建立PTR与阶调值的关系曲线。结论 抗透印PTR值在70.5%以下的纸张,适印40%以下阶调的图像;PTR值从71.0%开始不断增大,纸张的适印阶调范围也随之扩大;当PTR值达到73.8%左右时,即使实地色块也不会干扰到背面的图文。     

环境友好型聚天冬高吸水性树脂的合成

以可生物降解的高分子材料聚琥珀酰亚胺为原料,二胺为交联剂,合成了环境友好型聚天冬高吸水性树脂。考察了原料分子量、交联剂种类、交联剂用量、吸水温度以及吸水时间等对树脂吸水倍率的影响。结果表明,交联剂用量显著影响树脂的吸水倍率,以分子量为67500的聚琥珀酰亚胺为原料,己二胺为交联剂,交联剂浓度为1.5%时,树脂吸水倍率为1480。     

硫酸盐法蒸煮脱木素历程的近红外光谱表征法

利用近红外光谱法对木材硫酸盐法蒸煮过程脱木素历程进行了研究。结果表明,利用红外光谱能较好地表征木材的三段脱木素历程。这为下一步近红外光谱在线测量仪的开发奠定了理论基础。     

Polymer-grafted cellulose fibers. I. Enhanced water absorbency and tensile strength

To enhance the water absorbency of wood fibers, various acrylic monomers were grafted to these fibers using cerium IV initiation followed by base hydrolysis. The absorbent capacity of hydrolyzed methyl acrylate- or acrylonitrile-grafted wood pulp fibers was an order of magnitude greater than ungrafted pulp fibers. A portion of this enhanced absorbency could be attributed to graft-induced osmotic forces. Enhanced absorbency was relatively independent of wood fiber type. Paper handsheets incorporating 20% grafted fibers had a fivefold increase in absorbent capacity, a twofold increase in dry tensile strength, a threefold or greater increase in wet tensile strength, and were more stretchable. In addition to enhanced absorbent capacity, the rate of absorbency was approximately 50% greater. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1463–1469, 1997     

Superabsorbent polymeric materials. IV. Swelling behavior of crosslinked poly [sodium acrylate-co-N,N-dimethyl (acrylamidopropyl) ammonium propane sulfonate] in aqueous salt solution

A series of xerogels based on sodium acrylate (SA), N,N-dimethyl(acrylamidopropyl)ammonium propane sulfonate (DMAAPS), and N,N′-methylene bisacrylamide (NMBA) were prepared by inverse suspension polymerization. The water absorbency or swelling behavior for these xerogels in water or various saline solutions was investigated. Results obtained from this study revealed a water absorbency of 721 g H₂O/g sample in deionized water and 83 g H₂O/g sample in 0.9 wt % NaCl solution for a gel containing a 1.50 × 10 ⁻² molar fraction of DMAAPS. The absorbency in the chloride salt solutions decreased with an increase in the ionic strength of the salt. For the same ionic strength of various salt solutions, the swelling amount had the following tendency: Co ²⁺ > Ni ²⁺ > Cu ²⁺ for the higher ionic strength of 2.44 × 10 ⁻⁵–1.8 × 10 ⁻² M. The Co ²⁺, Ni²⁺, and Cu ²⁺ solutions induce approximately the same degree of swelling at the lower ionic strength of <2.44 × 10 ^minus;5 M. The pH effect on the water absorbency for these xerogels was also investigated. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66:499–507, 1997     

静电纺纳米纤维束的吸水保水及芯吸性能

运用环形电极作为接收装置获得静电纺纳米纤维束,对获得的纤维束进行吸水保水及芯吸性能研究,同时对不同沉积时间和不同纤维直径的纤维束进行吸水和保水性能对比。结果表明：随着沉积时间的增加,吸水倍率和保水率均有明显增加;随纤维直径的增加,吸水倍率和保水率减小,但相互之间差别不大。此外,对其芯吸高度进行对比发现：随着沉积时间和定向程度的增加,芯吸高度升高;随纤维直径的增加,芯吸高度下降。     

二次纤维生产高档生活用纸的探讨

探讨了以废纸为原料生产高档生活用纸的柔软性、吸液性和强度性能以及废纸中荧光物质和胶粘物的影响等若干问题.