Improved water resistance of particleboards bonded with glutaraldehyde-blended UF resin

One-layer particleboards were bonded with a UF-glutaraldehyde adhesive system. It was shown that 5 wt % of the glutaric aldehyde in the glue mix can reduce swelling and absorptivity of the boards without deterioration of their mechanical parameters below the requirements of the respective standards.     

On the warping behaviour of particleboards coated with melamine formaldehyde resin impregnated papers

Impregnated papers are widely used as decorative, protective and balance sheets in decorative laminates for the furniture, flooring and building industries. One important property of such composites is their warping behaviour. Especially for laminate flooring, warping of the lamellae is undesirable. In the present study the influence of important process parameters in the manufacturing of impregnated papers is quantitatively analyzed based on an industrial experiment carried out at an Austrian impregnation plant. Catalyst concentration, moisture content, resin loading and base paper supplier were varied according to an experimental design. The thermal properties of the impregnated papers and the warping behaviour of the corresponding boards were evaluated using response surface methodology. The resulting models allowed quantifying the relative importance of single factors on composite warp and defining the useful working range. Determination of the thermal properties of impregnated papers using DSC and TMA was not sufficient to predict laminate warp.     

On the warping behaviour of particleboards coated with melamine formaldehyde resin impregnated papers

Impregnated papers are widely used as decorative, protective and balance sheets in decorative laminates for the furniture, flooring and building industries. One important property of such composites is their warping behaviour. Especially for laminate flooring, warping of the lamellae is undesirable. In the present study the influence of important process parameters in the manufacturing of impregnated papers is quantitatively analyzed based on an industrial experiment carried out at an Austrian impregnation plant. Catalyst concentration, moisture content, resin loading and base paper supplier were varied according to an experimental design. The thermal properties of the impregnated papers and the warping behaviour of the corresponding boards were evaluated using response surface methodology. The resulting models allowed quantifying the relative importance of single factors on composite warp and defining the useful working range. Determination of the thermal properties of impregnated papers using DSC and TMA was not sufficient to predict laminate warp.     

Modelling of the moisture transfer process in particleboards

There were a number of studies on moisture transfer modelling of wood, but no systematic study for moisture transfer in particleboard with respect to usage or storage. The physical parameters of four kinds of particleboards were determined in this study. The unsteady-state diffusion coefficients and surface emission coefficients of moisture in particleboards were separated in one experimental period by using the method of linear regression. Then the moisture transfer processes in particleboard were analysed by using Finite Element Method (FEM), and the moisture absorption processes of four kinds of particleboards were observed experimentally. By comparing the computed results with the experimental results, it showed that the error was within 10%. Therefore, we came to the conclusion that the processes of moisture transfer in particleboard can be described by using FEM:     

大孔树脂纯化万寿菊花中叶黄素的工艺优化

目的:提高万寿菊花中叶黄素的纯度。方法:以葵花籽油微乳液作为提取剂提取万寿菊中的叶黄素。利用KOH-C₂H₅OH溶液对叶黄素粗提物进行皂化,再用大孔树脂进一步纯化。结果:静态试验中,HP-20型大孔树脂对叶黄素的吸附及解析效果最好,以80%乙醇溶液作为吸附溶剂,无水乙醇溶液作为解析溶剂,上样质量浓度为0.01 mg/mL,最佳静态吸附条件为温度30℃,吸附时间2.0 h, pH 7.0;最佳静态解析条件为温度40℃,解析时间1.0 h, pH为7.0。动态试验中,最佳上样质量浓度为0.01 mg/mL,上样流速为0.4 mL/min。经大孔树脂吸附后的叶黄素纯度可达61.72%。结论:大孔树脂纯化后的万寿菊中叶黄素的纯度明显提高。     

大孔树脂纯化苹果多酚的工艺优化

研究大孔吸附树脂对苹果多酚的纯化工艺。从6种大孔树脂中筛选出吸附性能和解吸性能良好的XAD7HP型大孔吸附树脂。在单因素试验基础上,设计正交实验,对大孔树脂纯化苹果多酚工艺进行优化。结果表明:最佳纯化条件为上样浓度1.46 mg/mL、上样pH值5.50、上样速度1.25 mL/min,洗脱剂种类为丙酮、洗脱剂浓度为90%、洗脱速度为1 mL/min。在此条件下,纯化后纯度高达80.1%,比纯化前提高了10倍多,且回收率高达90%。纯化后苹果多酚进行高效液相色谱分析,大部分杂质峰不再出现,检测出5种多酚成分。     

大孔树脂纯化番石榴多酚的工艺优化

考察大孔吸附树脂对番石榴多酚的吸附性能和纯化效果,确立番石榴多酚纯化的较优工艺。通过吸附、解吸实验,筛选出适合分离纯化番石榴多酚的大孔树脂,并确立其纯化工艺参数。结果表明,NKA-9是纯化番石榴多酚的最佳树脂,较佳吸附条件为上样多酚浓度为1.2mg/mL,pH2.0,上样速率为1mL/min,吸附率达到90.5%;较佳的洗脱条件为乙醇浓度50%,pH3.0,洗脱速率1mL/min,解吸率为89.3%。      

大孔树脂纯化番石榴多酚的工艺优化

考察大孔吸附树脂对番石榴多酚的吸附性能和纯化效果,确立番石榴多酚纯化的较优工艺.通过吸附、解吸实验,筛选出适合分离纯化番石榴多酚的大孔树脂,并确立其纯化工艺参数.结果表明,NKA-9是纯化番石榴多酚的最佳树脂,较佳吸附条件为上样多酚浓度为1.2mg/mL,pH2.0,上样速率为1mL/min,吸附率达到90.5％;较佳的洗脱条件为乙醇浓度50％,pH3.0,洗脱速率1mL/min,解吸率为89.3％.     

有机硅-酚醛树脂共聚物的合成与应用研究

该文利用酚醛树脂与有机硅化合物的接枝共聚反应制备了有机硅改性酚醛树脂,并将其与聚氧化乙烯(PEO)组成双元助留体系,应用于废纸脱墨浆的助留实验。实验结果表明,该双元体系能显著提高细小组分的一次留着率,而影响助留效果的主要因素有助剂的用量、有机硅改性酚醛树脂与PEO的比率、剪切力等。     

LX-1000HA树脂固定化单宁酶的工艺优化

优化LX-1000HA树脂固定化单宁酶的工艺条件。采用Box-Behnken试验设计和响应面分析方法进行优化,得出最佳工艺条件为酶液/载体比17.6(V/m)、pH 6.9、时间24h、温度36.5℃,该条件下固定化酶活力达到(18 495±200)U/g,酶活回收率为45.25%。     

马兰头总黄酮的大孔树脂纯化工艺优化

目的利用大孔树脂来纯化马兰头中粗黄酮,并确定纯化黄酮的最佳工艺。方法以黄酮回收率为指标,在单因素实验的基础上运用Box-Behnken响应面法(response surface methodology,RSM)设计三因素三水平实验以获得最佳纯化条件。结果 HPD-600大孔吸附树脂纯化马兰头粗提液的最佳工艺条件为:上样浓度0.93 mg/mL、上样pH为3.00、洗脱剂体积分数为84.17%、吸附速率1 BV/h,洗脱速率1 BV/h,此条件下马兰头总黄酮的质量分数由纯化前的4.11%提高到纯化后的50.80%。结论利用HPD-600型大孔树脂可以较好地纯化马兰头中的总黄酮。     

大孔树脂法纯化黑豆酯酶的工艺优化

目的对采用大孔树脂法纯化黑豆酯酶的工艺进行优化,确定其最佳工艺条件。方法首先通过静态吸附和洗脱试验,以黑豆酯酶的吸附率和洗脱率为指标,筛选最佳树脂。然后进行动态吸附和洗脱试验,研究上样稀释倍数、洗脱剂体积分数和洗脱剂体积3因素对洗脱率的影响。最后以黑豆酯酶得率和比活力为指标,用L_(16)(4~3)正交实验进行优化。结果通过筛选发现,D301R树脂吸附率和洗脱率都较高。动态吸附和洗脱实验中获得最佳工艺条件为:上样稀释倍数为40倍,洗脱剂体积分数为60%,洗脱剂用量为20 mL。在此条件下黑豆酯酶得率为(89.39±1.65)%,黑豆酯酶比活力(6.585±0.090)U/mg。结论与粗酶的纯度相比,优化后的大孔树脂法纯化黑豆酶工艺的提纯倍数达到6.143倍,为黑豆酯酶的提纯和有机磷农药残留的检测提供了科学依据。     

大孔树脂法纯化玉米须中槲皮素的工艺优化

目的获得大孔树脂法纯化玉米须中槲皮素的最优工艺条件。方法以吸附率、吸附量、洗脱率为指标,通过静态吸附与洗脱试验,确定综合指标最优树脂。通过单因素试验研究树脂质量、洗脱剂体积、洗脱剂体积分数对玉米须中槲皮素纯化效果的影响。最后利用L_(16)(4~5)正交表,以回收率为指标,对上述3个因素进行优化。结果通过筛选评价,D101型大孔树脂的综合性能最优。正交试验确定的最佳纯化工艺参数为:树脂质量1.5 g,洗脱剂体积15 m L,洗脱剂体积分数70%。在此条件下,通过3次验证试验,测得槲皮素的回收率为(91.41±1.63)%,纯化后样液中槲皮素纯度达到53.89%,较纯化前的纯度提高2.39倍。结论采用正交法优化大孔树脂法纯化玉米须中槲皮素的工艺具有可行性。     

黄麻/聚丙烯复合板材热压工艺参数的优化

研究了黄麻/聚丙烯复合板材的热压工艺与纤维板材性能的关系,主要探讨了热压温度、时间、压力对板材力学性能的影响,并利用三因子二次通用旋转组合试验,找出最优热压工艺参数为温度166.26℃、时间3.32 min、压力4.34 MPa,且由显著性检验结果、回归方程式及相互关系图可以看出复合板材的强度是随着成型温度和时间的增加呈先增加后减小的趋势。     

大孔树脂纯化寒富苹果渣多酚工艺优化

通过研究10种大孔树脂对寒富苹果渣多酚的静态吸附及解吸性能,筛选出一种最佳的大孔树脂,并利用这种树脂对寒富苹果多酚的纯化工艺进行优化。结果表明:HPD-826型树脂有较好的吸附和解吸性能,经实验确定其纯化苹果多酚的最佳动态吸附条件:苹果多酚提取液pH为5,浓度在0.5～0.8mg/mL之间,上样速度1mL/min;最佳洗脱条件:洗脱液为60%的乙醇溶液,解吸温度20℃,洗脱流速0.5mL/min。在此条件下,纯化样品的多酚纯度为52.26%。     

大孔树脂法纯化香菇柄中黄酮类化合物的工艺优化

目的获得大孔树脂法纯化香菇柄中黄酮类化合物的最优工艺条件。方法以吸附率、洗脱率为指标,通过静态吸附与洗脱试验,确定综合指标最优树脂。通过单因素试验研究树脂质量、洗脱剂体积、洗脱剂体积分数对香菇柄中黄酮类化合物纯化效果的影响。最后利用响应面分析法,以回收率为指标,对上述3个因素进行优化。结果通过筛选评价,D101型大孔树脂的综合性能最优。由响应面试验确定的最优纯化工艺参数为:洗脱剂体积分数65%,树脂质量1.5 g,洗脱剂体积25 mL。在此条件下,通过3次验证试验,测得黄酮类化合物的回收率为(65.61±0.24)%,纯化后回收液中黄酮类化合物的纯度为75.60%,是纯化前粗提液纯度的3.58倍。结论应用响应面法优化大孔树脂法纯化香菇柄中黄酮类化合物的工艺科学合理,可以有效地提高香菇柄中提取的黄酮类化合物的纯度。     

大孔树脂法纯化香菇柄中多酚的工艺优化

目的优化大孔树脂法纯化香菇柄中多酚类物质的工艺。方法以AB-8、NKA-9、D101、D280、DA201 5种大孔树脂对香菇柄中多酚的吸附率和解吸率为评价指标,通过静态吸附和解吸试验筛选最佳树脂。然后研究吸附温度、树脂质量、pH值大小、乙醇(洗脱剂)体积分数和乙醇(洗脱剂)体积5个因素对大孔树脂吸附和解吸香菇柄中多酚的影响。最后以香菇柄中多酚类物质得率为指标,采用L_9(3~3)正交试验对纯化工艺进行优化。结果通过筛选发现,NKA-9大孔树脂吸附率和解吸率较高。正交试验优化获得的最佳工艺条件为:pH=3,树脂质量0.50 g,吸附温度50℃,在此条件下纯化的香菇柄中多酚得率为51.71%±0.95%,纯度也较未纯化时提高了3.71倍。结论从香菇柄中开发利用香菇多酚具有可行性,本研究为香菇多酚的纯化和制备提供了科学依据。     

压榨法制备接骨木籽油工艺优化及其活性成分分析北大核心CSCD

为了促进接骨木籽的利用,采用压榨法制取接骨木籽油。以提油率为考察指标,通过单因素试验和正交试验对接骨木籽油的制备工艺进行了优化,同时对接骨木籽油的活性成分进行了分析。结果表明:压榨法制备接骨木籽油的最佳工艺条件为入榨水分含量7.0%、压榨机转速60 r/min、压榨温度90℃,在此条件下接骨木籽提油率为82.1%;接骨木籽油不饱和脂肪酸含量高达82.08%,维生素E、多酚、总黄酮的含量分别为23.8、32.7、38.3 mg/kg。接骨木籽油可作为一种优质植物油进行开发。     

黑莓果汁离子交换树脂脱酸工艺的条件优化

目的优化黑莓果汁离子交换树脂脱酸工艺条件。方法通过不同树脂、不同温度、不同流速的动态和静态实验,优化黑莓果汁的离子交换树脂脱酸工艺条件,并确定树脂的回收方法。结果最佳工艺条件为WZ140或IRA67型树脂,上样温度为10℃,流速30 BV/h,在此条件下,IRA67和WZ140树脂在第1次循环对黑莓果汁有机酸的交换量分别在160.4 g/L和115.8 g/L。树脂回收时先用3～4 BV的3%氢氧化钠溶液冲洗,流速3 BV/h,再用10 BV的去离子水以30 BV/h的流速冲洗即可。结论优化的离子交换树脂脱酸工艺条件适用于酸度较高的黑莓果汁的脱酸处理。     

Influence of pH of phenol-formaldehyde resin and thermal treatment on the properties of hardboard

Hydrogen ion concentration greatly affects the properties of finished hardboard products, since it serves the dual purpose of imporoving both strength and hydrophobic properties of the board. Improvement in the physical and mechanical properties was greater with increasing hydrogen ion concentration up to a certain pH (which is about 3.3 and 5 for boards pressed with resin and with pH adjusted by means of acid and alum respectively). However, higher hydrogen ion concentrations caused damage of cellulose fibers, thereby deteriorating the strength properties. In most cases the rate of improvement was much higher with alum adjustment of pH, especially when the boards were subsequently subjected to thermal treatment. With thermal treatment a greater improvement is attained at lower hydrogen ion concentrations than without it.