单宁改性酚醛树脂胶粘剂研究进展

在介绍可再生的绿色环保型生物质原料单宁的基础上,综述了黑荆树栲胶、落叶松栲胶以及马占相思栲胶等富含缩合单宁的生物质原料改性PF(酚醛树脂)胶粘剂的研究进展,并指出了单宁改性PF胶粘剂存在胶液黏度过大、单宁/甲醛的反应活性过高和胶液适用期过短等缺点。最后对单宁改性PF胶粘剂的研究方向进行了展望,指出利用单宁与改性木质素、玉米淀粉和生物油等生物质原料复配改性PF胶粘剂将成为重要的研究方向。     

基于灰色关联法高温堵剂性能评价

研发出了新型耐高温调剖堵水试剂磺化改性落叶松栲胶,其典型配方为:6.0 wt%磺化改性落叶松栲胶、2.5 wt%~3.0 wt%醛类交联剂、1.0 wt%~1.5 wt%酚类促进剂P-1,其他为水,用氢氧化钠将p H调节至8~10。通过实验对改性落叶松栲胶性能进行测试。试验表明,堵剂胶凝时间4~10 h可控,满足p H在4~10范围内使用,能用于100000 mg/L的较高矿化度地层,所成凝胶强度高。采用灰色关联法对温度、矿化度、组分浓度、p H等影响因素进行分析,各因素对磺化改性落叶松栲胶成胶时间和成胶强度的影响程度从大到小依次为温度、p H、栲胶浓度、矿化度。     

结构改性对钼系1,2-聚丁二烯熔液黏度和物理机械性能的影响

用调节剂对钼系1,2-聚丁二烯(PB)进行结构改性,并考察了其对物理机械性能的影响.结果表明,结构改性对1,2-PB的聚合活性无影响,所得产物溶液的剪切黏度明显降低,产物的相对分子质量变大,其分布变窄;改性后的钼系1,2-PB较改性前的凝胶含量增大,硫化胶的邵尔A硬度和磨耗降低,100%定伸应力增大,拉伸和撕裂强度略有降低.     

利用落叶松栲胶除垢的试验

为了不断扩大栲胶新用途,更好地为社会主义革命和社会主义建设服务,在兄弟单位应用橡椀栲胶除垢取得成功的好经验启发下,在厂党委的领导下,我厂于一九七六年五月份组成了三结合的落叶松栲胶除垢试验小组。一年多来,试验小组遵照毛主席关于“打破洋框框,走自己工业发展道路”的指示,采用落叶松栲胶进行除垢试验,取得了成功,并感到:用落叶松栲胶除垢,较之用橡椀栲胶的效果更为明显。试验结果证明:落叶松栲胶除垢,方法简单易行,经济安全,效果好,无腐蚀,可以代替碱煮除垢方法,从根本改变了过去除垢的工艺规程,改善了工人操作条件。此法尤其适合中、小型没有软水设备的采暖锅炉,对节省人力、物力、降低煤耗,都有很大的意义。现将我们落叶松栲胶除垢试验情况介绍如下:     

官能化丁苯橡胶门尼黏度的影响因素

对丁苯橡胶进行了改性,通过考察聚合反应转化率、相对分子质量调节剂的用量、结合苯乙烯含量、残余单体含量、聚合反应时间等参数对改性丁苯橡胶门尼黏度的影响,探讨了改性丁苯橡胶门尼黏度的影响因素。结果表明,在影响官能化丁苯橡胶门尼黏度的众多因素中,相对分子质量调节剂用量对门尼黏度影响最大,残留单体含量影响也很大。     

相对分子质量分布对静电纺丝PA6纤维直径的相关性研究

聚合物原料的相对分子质量及其分布直接影响其静电纺丝纤维直径的大小及分布。选用不同相对分子质量的PA6,通过共混获得不同相对分子质量分布的PA6溶液,通过静电纺丝得到PA6纤维毡,并研究了静电纺丝成形中所得PA6纤维直径及其分布与其相对分子质量及其分布的关系。结果表明:PA6的相对分子质量分布曲线和所获得纤维直径分布曲线相似,宽的相对分子质量分布导致静电纺丝纤维直径分布更宽;对于不同浓度的PA6溶液,PA6相对分子质量增大,纺丝溶液黏度增大,溶液浓度增大,其黏度也增大;PA6相对分子质量分布与其纤维直径分布有一定的相关性。     

UHMWPE/石蜡油溶液体系的黏度特性

以石蜡油(LP)为溶剂配制超高相对分子质量聚乙烯(UHMWPE)/LP溶液,运用正交设计方法,研究低剪切速率下UHMWPE的黏均相对分子质量(Mη)、溶液浓度和温度对UHMWPE/LP溶液体系黏度特性的影响。结果表明:UHMWPE/LP溶液的黏度随Mη及溶液浓度的增加而增加,随溶液温度的升高而降低;正交试验结果为UHMWPE的浓度对UHMWPE/LP溶液体系的黏度影响最大,Mη次之,在190~220℃下,温度影响较小。     

副产物含量对栲胶脱硫液性质的影响

在栲胶脱硫生产过程中除了主反应外,同时还伴随Na2S2O3,Na2SO4,NaSCN及NaHCO3等盐类生成的副反应.这些副产物的生成会影响栲胶脱硫液的性质,并最终影响整个脱硫循环工艺的稳定.为了避免这些影响,从表面张力、黏度和密度三个方面分析了Na2S2O3,Na2SO4,NaSCN和NaHCO3四种栲胶脱硫工艺的副产物对栲胶脱硫溶液的影响.结果表明,副产物的积累可以引起脱硫溶液表面张力的下降以及溶液黏度和密度的增加,从而引起脱硫工艺中操作条件的改变,最终影响整个系统的脱硫效率.     

超高相对分子质量聚乙烯的相对分子质量及其分布的测试方法

介绍了超高相对分子质量聚乙烯（PE-UHMW）的相对分子质量及分布的测试方法,主要有黏度法、流变法和凝胶渗透色谱法（GPC）。黏度法是目前应用最广泛的一种测试方法,主要采用高温乌氏黏度计,按照聚烯烃稀溶液的黏度测试方法进行,并通过经验公式计算得到PE-UHMW的相对分子质量。流变法是一种有效的测试PE-UHMW相对分子质量及其分布的方法,但目前该方法仍需改进。采用GPC法测试PE-UHMW的相对分子质量及其分布在技术上存在局限性。     

栲胶脱硫工艺中氧化栲胶溶液表面性质的研究

栲胶法脱硫工艺比ADA法应用更广,更具优越性.为揭示这种优越性,采用表面张力仪和电导率仪分别对氧化栲胶水溶液和ADA水溶液的表面性质进行了研究.结果表明,氧化栲胶是离子型表面活性剂,可降低溶液表面张力,并强化硫化氢或空气的气液传质速率;而ADA溶液不具有这种性质,这是栲胶脱硫技术优于ADA法脱硫技术的原因之一.氧化栲胶溶液的临界胶束浓度为0.53g/L,该值可作为栲胶脱硫溶液中氧化栲胶含量的最小值.     

落叶松树皮栲胶废渣各组分及其磺化产物的表面活性对比研究

分析了兴安落叶松树皮栲胶废渣的主要化学组分及各组分的磺化产物对木质素磺酸盐的表面活性的作用,发现树皮栲胶废渣制备的木质素磺酸盐表面活性、分散性能和净浆流动度较木材木质素磺酸盐高。表面活性和分散性能好的主要原因是栲胶废渣中可溶单宁和红粉的存在,而具有更好的净浆流动度是因为可溶单宁和酚酸的存在。     

Performances of larch (larix gmelini) tannin modified urea–formaldehyde (TUF) resin and plywood bonded by TUF resin

Tannin from larch (Larix gmelini) bark extracts, as a natural renewable resource, was used to prepare tannin–urea–formaldehyde (TUF) resin. The chemical structures of larch tannin and TUF resin were characterized by matrix‐assisted laser desorption/ionization‐time of flight mass spectrometry and ¹³C nuclear magnetic resonance. The thermal behaviors of TUF resin were evaluated by differential scanning calorimetry (DSC) and thermomechanical analysis (TMA). The performances of TUF resin were investigated by measuring the bond strength and formaldehyde emission of its bonded plywood. It was clearly shown that larch tannin is mainly composed of prodelphinidin repeating units. Phenolic groups were introduced into TUF resin mainly linked by methylene bond. Larch tannin has an adverse effect on the resin curing. However, it promoted the rigidity and flexibility of the glued system and upgraded the properties of plywood. Therefore, larch tannin could be applied in the modification of urea–formaldehyde resin. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41064.     

落叶松浓胶及甲醛含量对落叶松单宁胶粘剂粘度的影响

通过对不同配比的液体落叶松单宁胶粘剂粘度及干燥后的粉状落叶松单宁胶粘剂粘度进行测定,探明了液体落叶松单宁胶粘剂与粉状落叶松单宁胶粘剂粘度之间的关系,为制定合理的生产工艺参数提供了可靠的理论依据。     

落叶松浓胶及甲醛含量对落叶松单宁胶粘剂粘度的影响

通过对不同配比的液体落叶松单宁胶粘剂粘度及干燥后的粉状落叶松单宁胶粘剂粘度进行测定，探明了液体落叶松单宁胶粘剂与粉状落叶松单宁胶粘剂粘度之间的关系，为制定合理的生产工艺参数提供了可靠的理论依据。     

Effect of poly(ethylene glycol) on the hydrophobic interactions and rheology of proanthocyanidin biopolymers from Pinus radiata

The rheology of solutions of extracts from the bark of Pinus radiata was investigated in the presence of poly(ethylene glycol)s (PEGs) of different molecular weights. PEG with a molecular weight of 4600 (1% w/w) was sufficient to reduce the viscosity of a concentrated (40% w/w) pine tannin extract by one order of magnitude. The reduction of the viscosity was due to the inhibition of molecular association via hydrogen bonding and hydrophobic interactions between tannin and PEG and depended on the molecular weight of PEG. PEG effectively reduced the viscosity of polyphenolic tannins but retained high reactivity toward paraformaldehyde for adhesive formulations. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1254–1260, 2005     

桉树皮单宁分析

对广西高峰林场桃源分厂4年生的大叶桉和尾叶桉树皮的单宁含量进行了分析,并分别进行了栲胶的试制。分析结果表明:大叶桉和尾叶桉树皮单宁属于缩合类单宁,树皮单宁含量分别为7.6%和7.8%,纯度分别为67.9%和70.3%;大叶桉树皮栲胶单宁含量为65.4%,尾叶桉树皮栲胶单宁含量为63.3%。桉树皮可作为新品种栲胶原料,其栲胶值得推广应用。     

Development of wood-products adhesives from mangrove bark

Mangrove bark was extracted using either water, ethanol, acetone, or various binary mixtures of these, as solvent. With plywood panels as substrates, joints prepared with adhesives derived from these extracts were tested for strength properties. In terms of the quantity of extracts from mangrove bark, water was the most effective solvent, followed sequentially by ethanol and acetone. However, in terms of the tannin content of these extracts, the order of extraction effectiveness of these solvents was reversed. The use of solvent mixtures in tannin extraction did not produce an observable synergistic effect. The quantity of extract and its tannin content were dictated primarily by the predominant solvent in the binary mixture. The reactivity of mangrove bark extracts is influenced significantly by formaldehyde concentration, cure temperature, type, and pH of the adhesive medium. Adhesive joints of significant bond strength were obtained from mangrove tannin adhesives. Prolonged cure periods, particularly at elevated temperatures, have deleterious effects on the strength properties of these adhesive joints.     

Studies on pine bark extracts

Barks from six different species of pine were extracted with hot water. The yield, molecular weight, molecular weight distribution, viscosity, and gel time of the extracted polyphenolic materials were determined. The viscosity of the bark extracts was directly related to the molecular weight of the polyphenols. The amount of material extracted was increased by extracting with alkaline solution. Sulphitation of P. oocarpa bark hot water extracts reduced the viscosity without affecting the bonding properties of the adhesive.     

栲胶脱硫副产物对脱硫液粘度的影响

模拟栲胶脱硫液中副产物的积累过程,配制了含有不同浓度副产物的仿栲胶脱硫液,考察了栲胶脱硫液中Na2SO4、Na2S2O3、NaHCO3、NaSCN等副产物对脱硫液粘度的影响。结果表明,这些副产物的积累均会使栲胶脱硫液粘度增大,其中Na2S2O3和NaSCN是影响栲胶脱硫液粘度的主要因素;讨论了脱硫液粘度与主要副产物浓度之间的关系,用Excel软件进行了回归分析,得到很好的线性关系,为实际生产中估算栲胶脱硫液的粘度提供了一定的理论依据。     

Thermal Degradation of Condensed Tannins from Radiata Pine Bark

Abstract

In order to understand the influence of the inherent chemistry on the relative thermal stability of condensed tannins, the thermal degradation behaviors of various radiata pine bark extracts have been investigated using thermogravimetric analysis (TGA). Generally, results suggest pine bark extract fractions may be readily processed at temperatures below 200°C if co-extracted polysaccharides contents are minimized. Those extracts possessing greater carbohydrate content and lower tannin purity tend to have decreased thermal stability. The initial onset temperature for degradation of relatively crude extracts with high proportions of carbohydrate contents were relatively low (ca. 150°C), whereas extract purification to < 5% carbohydrate content gave increases in thermal stability of at least 50°C. The complicity of the carbohydrate content in the degradation of the tannin samples was also supported by calculated Ozawa activation energies and modulated TGA experiments. While no increase in the thermal stability was gained by acetylating the pendant hydroxyl groups of the pine bark tannin extract, chemical variations such as sulfonation have a large effect on thermal degradation, promoting lower degradation temperatures.