共查询到18条相似文献,搜索用时 125 毫秒
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《中国胶粘剂》2015,(11)
以马来酸(MAc)为催化剂,聚乙烯醇(PVA)和正丁醛为原料,通过缩醛化反应制备了一系列聚乙烯醇缩丁醛(PVB)树脂。考察了MAc掺量、m(正丁醛)∶m(PVA)及表面活性剂掺量等对PVB产率和胶膜力学性能的影响,并对PVB的结构及热稳定性等进行了分析。研究结果表明:以MAc为催化剂制备的PVB具有较好的热稳定性;当w(MAc)=9%、m(正丁醛)∶m(PVA)=0.6∶1.0和w[十二烷基硫酸钠(SDS)]=1.0%(均相对于PVA质量而言)时,PVB的产率相对最高,PVB胶膜的拉伸强度(49.40 MPa)和断裂伸长率(160%)相对最大;当m(PVB)∶m[环氧树脂(EP)]=0.3∶1.0时,PVB改性EP胶粘剂的剪切强度相对最大(为8.63 MPa)。 相似文献
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以聚乙烯醇(PVA)和糠醛(Fu)为主要原料,采用溶液涂敷法制备了聚乙烯醇缩糠醛(PVFu)复合纳滤膜,考查了聚乙烯醇的浓度、交联剂的用量及糠醛含量等对膜分离性能的影响。结果表明,在25℃,75%相对湿度条件下,通过质量分数5%的聚乙烯醇溶液与1%的糠醛缩醛化交联反应所制得的纳滤膜在1.0 MPa操作压力下对PEG600的截留率达到98.30%,水通量为11.3 L.m-2.h-1。随着操作压力的增加,通量呈线性增加,截留率也相应上升;该膜有较好的耐氯性;用红外光谱仪表征了复合膜的分子结构。用原子力显微镜(AFM)观察了复合膜的表面形态,用X射线衍射仪研究了聚乙烯醇缩糠醛固化后的结晶状态,并用动态活性氯测试法测试膜的耐氯性。 相似文献
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采用木质素和糠醛改性普通甲阶酚醛树脂。运用正交实验法得到木质素糠醛改性甲阶酚醛树脂的最佳反应条件,通过IR,DSC,TG分析和压缩性能测试对产物的热性能和力学性能进行了研究。结果表明,在苯酚100g,木质素40g,甲醛116.54g,糠醛34.28g,反应温度85℃,反应时间3h,体系pH值9的条件下得到的改性甲阶酚醛树脂固含量70%~80%,黏度850~1000mPa.s(25℃),热分解温度为258℃,与普通甲阶酚醛树脂(263℃)相比,耐热性稍差。所制备的改性酚醛塑料的压缩强度为1.07MPa,比普通酚醛塑料(0.73MPa)高,木质素和糠醛的引入提高了泡沫塑料的韧性。 相似文献
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以聚醚丙二醇(PPG600)、IPDI(异佛尔酮二异氰酸酯)、γ-缩水甘油醚氧丙基三甲氧基硅烷(KH-560)为主要原料,DMPA(2,2-二羟甲基丙酸)扩链合成支链型Si-WPU(硅氧烷水性聚氨酯)预聚体,再与PVB(聚乙烯醇缩丁醛)键合得到协同改性水性聚氨酯(PVB-Si-WPU)乳液,制备成膜。采用FT-IR(红外光谱)和TG(热重分析)法对胶膜进行表征,考察了R(—NCO/—OH)值和KH-560、PVB含量对乳液或胶膜性能的影响。研究结果表明:KH-560和PVB接枝到WPU分子链后,胶膜热稳定性得到一定提高;R值=2.6时,拉伸强度达到5.4 MPa,断裂伸长率降至237%;当KH-560和PVB添加量的质量分数分别等于6%和2%时(相对于纯WPU胶膜),PVB-Si-WPU胶膜的拉伸强度、断裂伸长率分别增长3.78、2.01倍,吸水率由38.0%降到15.4%。可见,KH-560和PVB的引入提高了WPU乳液的综合性能。 相似文献
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A series of novel hybrid materials have been prepared by the Diels-Alder reaction of poly(vinyl furfural) to maleimide compound followed by the sol-gel condensation of triethoxysilyl groups with water and acetic acid. The poly(vinyl furfural) having acetalization degree of 15% and 25% were obtained by the acid-catalyzed homogenous acetalization of poly(vinyl alcohol) with 2-furfural in a nonaqueous media. The resulting hybrid materials were characterized by the Fourier transform infrared spectroscopy, X-ray diffractions, scanning electron microscopy and atomic force microscopy. The thermal properties were investigated by differential scanning calorimetry, thermogravimetric and dynamic mechanical analysis. The thermal stability of the hybrid materials increased with increasing the inorganic content. 相似文献
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首先以蒽甲醛和聚乙烯醇(PVA)为原料、二甲基亚砜(DMSO)为溶剂、对甲苯磺酸(TsOH)为催化剂,反应得到蒽接枝改性聚乙烯醇(AnPVA)。然后利用混合溶剂凝胶法制备AnPVA水凝胶。通过差示扫描量热法(DSC)、拉伸等测试,研究水凝胶的力学等性能。结果表明,相比于纯PVA水凝胶,AnPVA水凝胶的力学性能得到了显著提高,在水凝胶中引入疏水基团是一种十分有效提高水凝胶力学性能的手段。AnPVA水凝胶浸泡于水中加热后无明显溶胀,有着优异的耐热和耐水性能,并且该水凝胶是物理交联网络,有着良好的循环重塑性能。 相似文献
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Shadpour Mallakpour Maryam Vahabi 《Polymer-Plastics Technology and Engineering》2015,54(15):1625-1633
In this investigation, nanocomposite films were fabricated by dispersion of poly(amide–imide)/CuO nanocomposites as nanofiller in the poly(vinyl alcohol) matrix via an ultrasonic process. The nanofiller was prepared and mixed with PVA matrix. After dispersion of nanofiller into the poly(vinyl alcohol), the mechanical properties of the nanocomposites were improved. For example, the addition of 6 wt% nanofiller into the poly(vinyl alcohol) matrix enhanced the tensile modulus by 39%. The residual weight at 800°C was 7% for pure poly(vinyl alcohol) while the nanocomposites illustrated 12–19% residue at this temperature. 相似文献
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《塑料、橡胶和复合材料》2013,42(6):254-258
AbstractCrosslinked chitosan/poly(vinyl alcohol) nanofibres were successfully prepared via electrospinning technique with heat mediated chemical crosslinking. The structure, morphology and mechanical properties of nanofibres were characterised by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), and tensile tester respectively. The SEM images demonstrated that crosslinked nanofibres exhibited a smooth surface and regular morphology. With increasing PVA, swelling of nanofabric increased. The mechanical properties of the fibre mats, as determined in a static tensile test, improved with increasing PVA composition owing to strong interaction between chitosan and poly(vinyl alcohol) molecular resulted from intermolecular hydrogen bonds. The crosslinked chitosan/poly (vinyl alcohol) nanofibrous mats have potential use as artificial skin and other tissue scaffold materials. 相似文献
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Sheikh Rasel 《Polymer-Plastics Technology and Engineering》2018,57(4):320-326
This paper focuses on the fabrication of cost effective and high performance poly(vinyl alcohol)/mica fibrous nanocomposites using electrospinning. Effective incorporation of fine particles of mica in poly(vinyl alcohol)/mica nanocomposites was examined and confirmed along with the evidence of good dispersion, by digital optical microscopy and scanning electron microscopy. The presence of mica improved the mechanical properties of the nanocomposites without affecting the thermal stability. The electrospun poly(vinyl alcohol) mats containing 20?wt% mica exhibited tensile strength of 13.29?MPa and tensile modulus of 180.3?MPa as compared to values of 3.92 and 83?MPa, respectively, for poly(vinyl alcohol) fiber mats. 相似文献