Tannin–resorcinol–aldehyde cold-set wood adhesives with only formaldehyde as hardener

Based on standard tannin adhesive formulations, tannin-resorcinol-glyoxal and tannin-resorcinol-glutaraldehyde cold-setting adhesives were prepared for wood glulam in this paper. Only less para-formaldehyde was added as hardener of adhesives. Both of them showed a rival tensile strength with tannin-resorcinol–formaldehyde adhesive. However they exhibited lower wood failure. The proportion of formaldehyde of the two are drastically decreased.     

纺织品甲醛污染及空间除醛技术

甲醛作为严重危害生命安全的常见有毒致癌物质已受到人们的高度重视。目前国内外对甲醛的研究主要集中在医学和居室空气质量控制范畴,对纺织品甲醛感染系统性研究的报道还不多见。研究产业用纺织品、装饰用纺织品和仓存空间的甲醛污染问题,介绍三大纺织品产生甲醛超标的根源、释放特点和治理措施等,同时分析空间甲醛污染的可能性和研究进展。     

Controlling formaldehyde emissions with boiler ash

Fluidized wood ash reduces formaldehyde in air from about 20 to <1 ppmv. Methanol is removed to a much lower extent. The efficiency of formaldehyde reduction increases with increasing moisture content of the ash. Sorption of formaldehyde to ash can be substantially accounted for by partitioning to the water contained in the ash followed by rate-controlling binding to the ash solids. Adsorption occurs at temperatures of up to 165 degrees C; oxidation predominates thereafter. It is proposed that formaldehyde could be stripped from an air stream in a fluidized bed containing ash, which could then be returned to a boiler to incinerate the formaldehyde.     

明胶对甲醛捕获条件的研究

为了开发出能应用于食品中的新型甲醛捕获剂,本文以明胶为研究对象,采用单因素实验分析了时间、温度、p H、浓度对明胶与甲醛的反应特性。在单因素实验的基础上,以甲醛捕获率为响应值,通过Box-Behnken中心组合实验对明胶作为甲醛捕获剂的捕获条件进行优化,进一步研究了明胶对甲醛的捕获特性,结果表明明胶的最佳捕获条件为:捕获时间10 h、捕获温度30℃、p H8.0、明胶浓度1.0%,甲醛捕获率可达80.97%。      

改性壳聚糖对合纤织物整理的结合状态分析

为探讨壳聚糖对抗菌整理合纤织物的结合状态,采取3种工艺配方将改性的季铵盐壳聚糖(HTCC)配制成改性壳聚糖抗菌整理液。以腈纶针织面料和维纶包装袋为试样,用改性壳聚糖抗菌整理液对织物进行后整理。通过扫描电镜观察和傅里叶红外光谱分析,探究改性壳聚糖在纤维上的吸附结合状况。研究结果表明:在黏合剂体系作用下,改性后的季铵盐壳聚糖与腈纶及维纶织物都发生了黏附结合,织物表面确实有改性壳聚糖的吸附存在,从而达到了对合纤织物抗菌整理的目的。     

Alcohol oxidase- and formaldehyde dehydrogenase-based enzymatic methods for formaldehyde assay in fish food products

For Gadoid fishes, formaldehyde can be generated in tissues in huge amounts during endogenous enzymatic degradation of natural osmoprotectant trimethylamine-N-oxide. This paper describes two enzymatic methods for assay of formaldehyde in fish food products using alcohol oxidase (AOX) and formaldehyde dehydrogenase (FdDH) isolated from the thermotolerant methylotrophic yeast Hansenula polymorpha. AOX-based method exploits an ability of the enzyme to oxidise a hydrated form of formaldehyde to formic acid and hydrogen peroxide monitored in peroxidase-catalysed colorimetric reaction. In FdDH-based method, a monitored coloured formazane is formed from nitrotetrazolium salt during reduction by NADH, produced in formaldehyde-dependent reaction. It was demonstrated an applicability of both methods for assay of formaldehyde in fish products. The optimal protocols for analysis procedures have been elaborated and analytical parameters of both enzymatic methods have been established. The both methods were demonstrated that some fish products (hake and cod) contain high formaldehyde concentrations (up to 100 mg/kg wet weight).     

纯棉府绸低甲醛树脂整理工艺

采用低甲醛树脂整理剂对纯棉府绸进行抗皱整理.讨论了树脂用量、pH值、焙烘条件等因素对整理效果和织物性能的影响,优化的工艺条件为:树脂用量80g/L,pH值4.3,焙烘温度155℃,焙烘时间3.5 min,整理后织物的平整度提高、色差减少和强力损失降低.     

不同纺织品甲醛检测标准对比及检测结果回归分析

对不同纺织品甲醛检测标准进行了对比研究,对各标准间差异对甲醛检测结果的影响和各检测结果间的回归性进行了分析。结果表明:水萃取法的GB(ISO)标准与JIS标准(间苯三酚法)间差异较大。蒸汽吸收法的GB(ISO)标准与JIS标准间差异及与AATCC标准间某些差异较大;甲醛检测结果由高到低依次为:AATCC标准释放甲醛、GB(ISO)标准释放甲醛、GB(ISO)标准游离和水解甲醛、JIS标准游离和水解甲醛;不同标准甲醛检测结果间具有十分显著的线性回归关系,且拟合程度很好。     

Bonding performance of heat treated wood with structural adhesives

Bonding of untreated, intermediate (hydro-thermolysed) and heat treated wood with melamine-urea-formaldehyde (MUF), phenol-resorcinol-formaldehyde (PRF) and polyurethane (PUR) adhesives was studied. An industrial heat treatment process (Plato ^®) was used, which included two separate heat treatment stages and a drying stage in-between. Laminated beams having four lamellas were prepared from untreated and treated timber for mechanical testing of the bond lines. The results of the tests showed that heat treatment affected the shear strength and the delamination of the laminated wood depending on the adhesive system used for bonding. The PUR and MUF adhesives performed in a rather similar way, and better than the PRF adhesive. The shear strength of laminated wood bonded with the waterborne MUF and PRF adhesives decreased for the specimens made of hydro-thermolysed timber and decreased further for the specimens made of fully heat treated timber. The difference in adhesive bond shear strength between untreated, intermediate and fully treated wood was less obvious in the case of the PUR adhesive. Delamination of the PRF bond line decreased drastically for all the specimens made of heat treated timber.     

Release of acetic acid and formaldehyde from particleboards bonded with phenolic resins

The gas analysis method (EN 717-2:1994), originally destined for measuring the formaldehyde release from wood-based panels, can also be used to determine the emanation of volatile organic acids such as acetic acid. However, the profile of release of formaldehyde and acetic acid seems to be quite different in the course of the gas analysis test.     

免烫整理吸醛消臭添加剂PT-03

用纳米添加剂PT-03处理纤维素纤维织物，可降低免烫整理织物中的游离甲醛，提高平整度和耐磨性。通过测试PT-03对油脂型气体和苯乙烯气体的吸附能力可知，PT-03具有很强的消臭能力。     

Preparation and characterization of urea–formaldehyde adhesives modified with glyoxalated tannin

European Journal of Wood and Wood Products - Urea–formaldehyde (UF) resins are the most important type of adhesive for the preparation of wood-based panels, due to its good performance and...     

酶催化光度法测定酒中微量甲醛的研究

研究了HCHO/NAD+/FDH体系的最佳条件,建立了简便测定甲醛的吸光光度法。实验发现:在温度为35℃、pH为7.0的条件下催化反应15min,所形成的催化反应产物在340nm处有最大吸收,甲醛含量在0.01452～0.2904μmol/mL范围内成良好线性关系,回归方程为:A=2.6604C-0.02476(C为μmol/mL),其测定相关系数为0.9998,检测限达0.0100μmol/mL(S/N=3),本法所用仪器简单、操作方便、选择性好,应用于酒中甲醛的测定结果令人满意。     

超低甲醛阻燃整理工艺探讨

通过对纯棉帆布阻燃整理工艺的选择、参数的优化，确定最佳工艺为：树脂70g／L，阻燃剂400g／L，磷酸20g／L，纤维保护剂40g／L，轧液率70％，180℃焙烘90s。经测试，整理后织物的阻燃效果理想，手感较好，甲醛含量仅16mg／kg，且耐水洗。     

甲醛交联高温溶胀法制备非晶颗粒态玉米淀粉

甲醛作为交联剂,高交联改性玉米淀粉后水域加热至78℃制备非晶颗粒态淀粉。考察不同的交联剂用量对原玉米淀粉非晶化的影响。用偏光显微镜观测处理后淀粉颗粒结构,结合X射线衍射曲线确认淀粉由多晶态向非晶态的变化。结果表明,当交联剂甲醛用量达到12.5%(淀粉干基)的时候,玉米淀粉可由多晶颗粒态的原淀粉制备出只含无定形结构的非晶颗粒态淀粉。