An efficient and mild recycling of waste melamine formaldehyde foams by alkaline hydrolysis

Melamine formaldehyde foam(MFF)generates many poisonous chemicals through the traditional recycling methods for organic resin wastes.Herein,a high MFF degradation ratio of ca.97 wt.%was achieved under the mild conditions(160℃)in a NaOH–H2O system with ammelide and ammeline as the main degradation products.The alkaline solvent had an obvious corrosion effect for MFF,as indicated by scanning electron microscopy(SEM).The reaction process and products distribution were studied by Fourier-transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS),and ^(13)C nuclear magnetic resonance(NMR).Besides,the MFF degradation products that have the similar chemical structures and bonding performances to those of melamine can be directly used as the raw material for synthesis of melamine urea-formaldehyde resins(MUFs).Moreover,the degradation system demonstrated here showed the high degradation efficiency after reusing for 7 times.The degradation process generated few harmful pollutants and no pre-or post-treatments were required,which proves its feasibility in the safe removal or recovery of waste MFF.

Indoor Formaldehyde Removal Techniques through Paints: Review

Due to its ability to cause illnesses and discomfort even at low concentrations, formaldehyde pollution of indoor air poses a significant risk to human health. Sources of formaldehyde in indoor environments include textiles, paints, wallpapers, glues, adhesives, varnishes, and lacquers;furniture and wooden products like particleboard, plywood, and medium-density fiberboard that contain formaldehyde-based resins;shoe products;cosmetics;electronic devices;and other consumer goods like paper products and insecticides. According to the World Health Organisation, indoor formaldehyde concentrations shouldn’t exceed 0.1 mg/m3. The methods include membrane separation, plasma, photocatalytic decomposition, physisorption, chemisorption, biological and botanical filtration, and catalytic oxidation. Materials based on metal oxides and supported noble metals work as oxidation catalysts. Consequently, a paint that passively eliminates aldehydes from buildings can be developed by adding absorbents and formaldehyde scavengers to the latex composition. It will be crucial to develop techniques for the careful detection and removal of formaldehyde in the future. Additionally, microbial decomposition is less expensive and produces fewer pollutants. The main goal of future research will be to develop a biological air quality control system that will boost the effectiveness of formaldehyde elimination. The various methods of removing formaldehyde through paints have been reviewed here, including the use of mixed metal oxides, formaldehyde-absorbing emulsions, nano titanium dioxide, catalytic oxidation, and aromatic formaldehyde abating materials that can improve indoor air quality.

Comprehensive Analysis of Indoor Formaldehyde Removal Techniques:Exploring Physical,Chemical,and Biological Methods

This research focuses on the evaluation of diverse approaches for removing formaldehyde from indoor environments,which is a significant concern for indoor air quality.The study systematically examines physical,chemical,and biological methods to ascertain their effectiveness in formaldehyde mitigation.Physical methods,including air circulation and adsorption,particularly with activated carbon and molecular sieves,are assessed for their efficiency in various concentration scenarios.Chemical methods,such as photocatalytic oxidation using titanium dioxide and plasma technology,are analyzed for their ability to decompose formaldehyde into non-toxic substances.Additionally,biological methods involving plant purification and microbial transformation are explored for their eco-friendly and sustainable removal capabilities.The paper concludes that while each method has its merits,a combined approach may offer the most effective solution for reducing indoor formaldehyde levels.The study underscores the need for further research to integrate these methods in a practical,cost-effective,and environmentally sustainable manner,highlighting their potential to improve indoor air quality significantly.

Evaluation of Formaldehyde as a Potential Cause of Olfactory Dysfunction in Hairdressers

Objective: The aim of this study was to compare the olfactory function between hairdressers exposed to formaldehyde and unexposed controls, as exposure to toxic agents is a potential cause of olfactory disorders in humans. Hairdressing professionals frequently encounter formaldehyde, a component found in hair products that are known to have various toxic effects on the human body, including alterations in the sense of smell. Methods: A total of 32 hairdressing volunteers exposed to formaldehyde and 32 non-exposed volunteers matched for age, sex, education and smoking status underwent the University of Pennsylvania Smell Identification Test (UPSIT®). Results: The findings demonstrated a decrease in UPSIT® olfactory test scores and a higher degree of olfactory loss among hairdressers exposed to formaldehyde (mean UPSIT® scores: 30.6 vs 35.1, p Conclusion: Occupational exposure of hairdressers to formaldehyde is associated with diminished olfactory function. Education approach and promotion of personal protective equipment usage should be encouraged.

Evaluation of Formaldehyde as a Potential Cause of Olfactory Dysfunction in Hairdressers

Objective: The aim of this study was to compare the olfactory function between hairdressers exposed to formaldehyde and unexposed controls, as exposure to toxic agents is a potential cause of olfactory disorders in humans. Hairdressing professionals frequently encounter formaldehyde, a component found in hair products that are known to have various toxic effects on the human body, including alterations in the sense of smell. Methods: A total of 32 hairdressing volunteers exposed to formaldehyde and 32 non-exposed volunteers matched for age, sex, education and smoking status underwent the University of Pennsylvania Smell Identification Test (UPSIT®). Results: The findings demonstrated a decrease in UPSIT® olfactory test scores and a higher degree of olfactory loss among hairdressers exposed to formaldehyde (mean UPSIT® scores: 30.6 vs 35.1, p Conclusion: Occupational exposure of hairdressers to formaldehyde is associated with diminished olfactory function. Education approach and promotion of personal protective equipment usage should be encouraged.

LncRNA FAS-AS1转染对K562细胞生物学行为的影响

目的探究LncRNA FAS-AS1对K562白血病细胞生物学行为的影响。方法取对数生长期的K562细胞培养分为空白对照组(正常培养,不做任何处理),阴性对照组(转染LncRNA FAS-AS1空质粒),实验组(Lnc RNA FAS-AS1)。MTT法检测细胞增殖情况,Western blot检测细胞中mTOR、AMPK蛋白含量,流式细胞仪检测细胞凋亡情况。结果与空白对照组和阴性对照组相比,实验组K562细胞FAS-AS1 mRNA表达显著上升(P<0.05),但空白组与阴性对照组细胞中FAS-AS1 mRNA表达比较差异无统计学意义(P>0.05)。随着培养时间的延长,实验组K562细胞的增殖率显著低于对照组(P<0.05),但空白与阴性对照组细胞增殖率比较差异无统计学意义(P>0.05)。实验组凋亡率显著高空白对照和阴性对照组(P<0.05),而空白对照组与阴性对照组凋亡率比较差异无统计学意义(P>0.05)。实验组K562细胞AMPK蛋白表达水平显著高于空白对照组和阴性对照组(P<0.05),而空白对照组和阴性对照组K562细胞中表达水平蛋白mTOR、AMPK比较差异无统计学意义(P>0.05)。结论LncRNA FAS-AS1过表达对K562白血病细胞的生物学行为有显著影响,能够降低细胞的增殖数量及增殖活性,可能与活化AMPK基因进而阻断mTOR活性相关。

基于FXR-Srebp1c-FAS通路及CD36探讨祛痰活血方抗非酒精性脂肪性肝病的机制

目的 以内源性脂肪酸合成相关法尼醇X受体(farnesoid X receptor,FXR)-固醇调节元件结合蛋白-1c(sterol regulatory element-bindingprotein-1c,Srebp1c)-脂肪酸合成酶(fatty acid synthase,FAS)通路及外源性脂肪酸摄入相关的白细胞分化抗原36(cluster of differentiation 36,CD36)为切入点,探讨祛痰活血方抗非酒精性脂肪性肝病(non-alcoholic fatty liver disease,NAFLD)的分子机制。方法 雄性C57BL/6J小鼠,随机分为对照组、模型组、祛痰活血方组和易善复组,每组各10只。模型组、祛痰活血方组和易善复组给予高脂饲料喂养,4周后祛痰活血方组和易善复组开始给药干预,给药8周后取各组小鼠血清用于生化检测;肝组织用于病理、肝脏总胆固醇(cholesterol,TC)、甘油三酯(triglyceride,TG)含量及FXR、Srebp1c、FAS、CD36基因及蛋白表达的检测。结果 与对照组比较,模型组小鼠体质量、肝质量明显增加(P<0.05);肝组织病理结果及肝脏TC、TG含量的升高(P<0.01)均提示明显脂肪变性;肝组织FXR、Srebp1c的m RNA表达水平,以及CD36的m RNA和蛋白表达均明显上升(P<0.01),FAS蛋白表达下降(P<0.05);与模型组比较,祛痰活血组小鼠体质量、肝质量均明显降低(P<0.01);肝组织脂肪变性明显减轻;肝组织中FXR m RNA表达明显升高(P<0.01),Srebp1c、FAS、CD36的m RNA及蛋白表达均明显降低(P<0.05)。结论 外源性脂肪酸摄入增加可能是高脂引起的NAFLD的主要成因,祛痰活血方既抑制外源性脂肪酸摄入,亦减少内源性脂肪酸合成,双向调节改善NAFLD。

FasL、Caspase-9表达水平对肝细胞性肝癌患者介入治疗后预后的判断价值分析

目的 探讨介入治疗前后肝细胞性肝癌(HCC)患者Fas配体(FasL)、半胱氨酸天冬氨酸蛋白酶-9(Caspase-9)表达变化及意义。方法 选取68例接受介入治疗的HCC患者为研究对象。对比治疗前后HCC患者FasL、Caspase-9水平。统计HCC患者复发情况,并分为复发组和未复发组。对比复发组和未复发组临床资料、治疗前后FasL、Caspase-9水平。Logistic多因素回归分析影响HCC患者治疗后复发的危险因素。制作受试者工作特征曲线(ROC),以曲线下面积(AUC)评价FasL、Caspase-9对HCC患者治疗后复发的预测价值。结果 与治疗前相比,治疗后患者FasL水平降低(P<0.05),Caspase-9水平升高(P<0.05)。随访结束,介入治疗的HCC患者复发发生率为47.06%(32/68)。复发组肿瘤最大直径、肿瘤个数、治疗后FasL水平高于未复发组(P<0.05),治疗后Caspase-9水平低于未复发组(P<0.05)。多因素分析结果显示:肿瘤最大直径(OR=2.619,95%CI:1.126~6.092)、治疗后FasL(OR=2.134,95%CI:1.264~3.602)、治疗后Caspase-9(OR=0.975,95%CI:0.954~0.997)是HCC患者治疗后复发的相关因素(P<0.05)。ROC分析显示,治疗后FasL、Caspase-9及两者联合检测对预测HCC患者治疗后复发灵敏度分别为78.12%(95%CI:59.56%~90.06%)、71.87%(95%CI:53.02%~85.60%)、93.75%(95%CI:77.78%~98.91%),特异度分别为72.22%(95%CI:54.57%~85.21%)、80.56%(95%CI:63.43%~91.20%)、72.22%(95%CI:54.57%~85.21%),AUC分别为0.794(95%CI:0.679~0.883)、0.785(95%CI:0.668~0.875)、0.867(95%CI:0.763~0.937)。结论 介入治疗后HCC患者FasL水平降低、Caspase-9水平升高。治疗后FasL、Caspase-9可作为临床评估HCC患者治疗后复发的重要参考指标。

基于GA-BP-FA算法的多轴铣削残余应力优化

提出了面向多轴铣削GH4169的残余应力控制的GA-BP-FA多目标优化模型,运用遗传算法(GA)优化BP神经网络的初始权值和阈值,提升神经网络算法的收敛速度和预测精度。基于GA-BP算法建立了铣削残余应力预测模型,并分析了铣削工艺参数对残余应力的影响。以获得最小残余拉应力/最大残余压应力为目标,基于萤火虫算法(FA)对铣削工艺参数进行优化。研究结果表明,所建立的残余应力的GA-BP预测模型具有较高的预测精度,两个方向的平均误差分别为18.9%和16.7%。经FA算法优化后,所选参数阈内最优工艺参数为切削倾角Φ=85°,切削速度v=20 m/min,每齿进给量f_(z)=0.01 mm/z。优化后σ_(x)方向的残余压应力-463.43 MPa和σ_(y)方向的残余压应力-686.93 MPa。

鱼类肠道益生地衣芽孢杆菌FA6发酵工艺的响应面法优化

研究以地衣芽孢杆菌FA6活菌数为指标,采用单因素实验和响应面法实验优化了地衣芽孢杆菌FA6发酵培养基和发酵条件,获得了地衣芽孢杆菌FA6最佳发酵培养基:70 g/L可溶性淀粉、40 g/L酪蛋白胨、2 g/L K2HPO4、1 g/L KH_(2)PO_(4)、2 g/L Na_(2)HPO_(4)、2 g/L MgSO_(4)和8 g/L NaCl;以及最佳发酵条件:初始pH 7.0、接种量1%、发酵温度28.8℃、发酵时间31h、装液量50 mL/250 mL和转速160 r/min。在此发酵培养基和发酵条件下,地衣芽孢杆菌FA6活菌数为7.97×10^(9)CFU/mL,较优化前提高了8.1倍。最佳发酵工艺的获得,将能够为鱼源芽孢杆菌的高密度生产,产业化应用提供基础。

基于Fas/FasL介导的凋亡信号通路研究通管方对输卵管炎性不孕模型大鼠的作用机制

目的:探讨通管方对输卵管炎性不孕(SI)模型大鼠输卵管组织中Fas/FasL通路的影响。方法:采用经阴道内接种混合菌液的方法,建立输卵管炎性不孕大鼠模型。造模后,77只SD雌性大鼠随机分成空白组、假手术组、模型组、妇可靖胶囊组(0.29 g·kg^(-1)·d^(-1))、通管方低剂量组(7.515 g·kg^(-1)·d^(-1))、通管方中剂量组(15.03 g·kg^(-1)·d^(-1))、通管方高剂量组(30.06 g·kg^(-1)·d^(-1)),各组大鼠分别灌胃给药28 d后处死并取材。采用蛋白免疫印迹法(WB)检测SI模型大鼠输卵管组织中Fas、FasL蛋白及Caspase-1的表达水平,酶联免疫吸附法(ELISA)检测SI模型大鼠血清IL-4、IL-10、Caspase-1的表达变化。结果:与空白组比较,模型组血清中IL-4和IL-10的水平均明显降低,血清和输卵管组织中的Caspase-1水平明显升高(P<0.01);与模型组比较,通管方各剂量组和妇可靖胶囊组降低了血清和输卵管组织中的Caspase-1的表达(P<0.01),上调了血清中IL-4和IL-10水平、输卵管组织中Fas和FasL蛋白的表达(P<0.05,P<0.01)。其中,通管方高剂量组的作用均明显优于其他剂量组和妇可靖胶囊组(P<0.05,P<0.01)。结论:通管方可能通过调控Fas/FasL凋亡信号通路而消除SI模型大鼠输卵管炎症。

基于ikPCA-FABAS-KELM的短期风电功率预测

为了增强在短期风电功率预测领域中传统数据驱动机器学习模型的精度,提出基于ikPCA-FABAS-KELM的短期风电功率预测模型.首先,对主成分分析进行改进,提出可逆核主成分分析(ikPCA),在保证数据特征的同时,降低输入数据的复杂度,以提升模型运行速度;其次,引入萤火虫个体吸引策略对天牛须算法(BAS)进行改进,提出FABAS算法;最后,利用FABAS算法对核极限学习机(KELM)的正则化参数C和核参数γ进行寻优,降低人为因素对模型盲目训练的影响,提高模型预测精度.仿真结果显示,提出的预测模型有效提高了传统模型的预测精度.

桥本甲状腺炎UGRP1与Fas介导的凋亡通路的相关性研究

目的探讨桥本甲状腺炎(HT)中子宫球蛋白相关蛋白1(UGRP1)与Fas介导的凋亡通路的相关性。方法免疫组化(IHC)法检测正常人、HT患者甲状腺细胞UGRP1的表达。在体外用质粒转染大鼠甲状腺细胞(FRTL-5细胞),分别为空载体质粒组、UGRP1质粒组、Fas质粒组,采用实时荧光定量逆转录PCR(RT-qPCR)方法检测各组细胞Fas、UGRP1基因表达水平的变化。结果HT患者甲状腺细胞UGRP1表达呈阳性,正常人甲状腺细胞UGRP1表达呈阴性。转染UGRP1质粒组的Fas基因表达水平较空载体质粒组无明显变化(1.0850±0.1249 vs1.0210±0.1139),转染Fas质粒组的UGRP1基因表达水平较空载体质粒组显著升高(P<0.0001,5.8070±0.3232 vs0.7527±0.0760)。结论桥本甲状腺炎UGRP1高表达可能与Fas介导的凋亡通路相关。

Degradation of Residual Formaldehyde in Fabric by Photo-catalysis

The residual formaldehyde （HCHO） in fabric was degraded using photo-catalysis assisted by the compound catalyst of nano-TiO2 and nano-ZnO. The effects of several factors on the degradation, such as the composing of catalyst, irradiation time, pH value and the H2CHO concentration of the immersed solution were investigated. Results showed that H2CHO of the immersed solution had degraded 93% after 5 h irradiation, and the degradation ratio of formaldehyde could be improved and the aging of the fabric can be avoided with the addition of ZnO nanoparticles and pH value of the immersed-fibric solution. The fabric with residual formaldehyde about 1 800 μg/g can be efficiently treated to satisfy the China National Standard （GB/2912.1-1998） with the photo-catalytic degradation.

疏肝健脾颗粒对大鼠乳腺癌癌前病变组织Fas、FasL表达的影响

目的:观察疏肝健脾颗粒对模型大鼠乳腺癌癌前病变组织Fas、FasL表达的影响,探讨其阻断乳腺癌癌前病变发展的机制。方法:90只SD大鼠,随机分为6组,正常对照组、模型组、三苯氧胺组及疏肝健脾颗粒低剂量组、中剂量组、高剂量组。以雌孕激素与DMBA联合诱导乳腺癌癌前病变模型,各组分别给予生理盐水、三苯氧胺、疏肝健脾颗粒不同剂量干预60 d后,进行组织病理学及Fas、FasL表达的免疫组化检测。结果:模型组大鼠乳腺癌前病变率为69.2%,疏肝健脾颗粒各剂量组及三苯氧胺组的癌前病变发生率均低于模型组(P<0.01),模型组和疏肝健脾颗粒中、低剂量组部分大鼠乳腺组织发生浸润癌。正常对照组大鼠乳腺组织Fas蛋白表达较高,FasL蛋白表达在模型组大鼠乳腺组织表达较高,疏肝健脾颗粒各剂量组和三苯氧胺组Fas蛋白表达增强,FasL蛋白表达减弱,与模型组比较差异显著(P<0.05或P<0.01)。结论:疏肝健脾颗粒可以显著降低DMBA诱导的大鼠乳腺癌癌前病变的发生率,调控乳腺癌癌前病变组织Fas、FasL的表达是其部分作用机制。

Effect of polytetrafluoroethylene hollow fiber microstructure on formaldehyde carbonylation performance in membrane contactor

Membrane contactor is regarded as a promising method for reaction and process intensification. The feasibility of formaldehyde carbonylation to synthesize glycolic acid using polytetrafluoroethylene(PTFE)membrane contactor has been proved in our previous study. In this paper, the effect of membrane microstructure on process performance was further investigated. Three porous PTFE hollow fibers with different pore sizes and one polydimethylsiloxane(PDMS)/PTFE composite membrane with dense layer were fabricated for comparison. The physical and chemical properties of four membranes, including chemical composition, morphology, contact angle, liquid entry pressure, thermodynamic analysis and gas permeability, were systemically characterized. Experiments of formaldehyde carbonylation under different reaction conditions were conducted. The results indicated that the yield of glycolic acid increased with decreasing pore size for porous membranes, which was due to the improvement of wetting behavior. The dense layer of PDMS in composite hollow fiber could effectively prevent the solvent from entering membrane pores, thus the membrane exhibited the best performance. At reaction temperature of 120℃ and operation pressure of 3.0 MPa, the yield of glycolic acid was always higher than 90% as the mass ratio of trioxane and phosphotungstic acid increased from 0.2:1 to 0.8:1. The highest turnover frequency was up to 26.37 mol·g^(-1)·h^(-1). This study provided a reference for the understanding and optimization of membrane contactors for the synthesis of glycolic acid using solvent with low surface tension.

Curing Process of Phenol Formaldehyde Resin for Plywood under Vacuum Conditions

The study characterized the curing behaviors of phenol formaldehyde(PF)resin under different vacuum degrees and explored the properties of 9-ply plywood panels hot-pressed under both vacuum and atmospheric conditions.The changes in core temperature and moisture content of the plywood mats during hot pressing were investigated as well.It was found that the gel times and gel temperatures of PF resin decreased with the increase of vacuum degree using a self-made device.FTIR spectra indicated the degree of polycondensation of hydroxymethyl gradu-ally increased with the increase in temperature.It was also observed that a higher degree of vacuum led to a slower polycondensation reaction rate of PF resin.During different hot-pressing processes,the bonding strengths in the innermost and uppermost gluelines of the vacuum hot-pressed plywood panels were up to 30%–50%higher than their counterparts of conventional hot-pressed products.A less difference in the bonding strengths between these two gluelines was also observed for vacuum hot-pressed products.In addition,the core of vacuum hot-pressed plywood was found to have a greater heating rate and higher temperature at thefinal stage of hot pressing,which was beneficial to cure the PF resin.The results from this study indicate a promising potential of introducing a vacuum during hot pressing to improve the quality and productivity of plywood products and provide a basis for adopting vacuum to hot press wood composites.

Rheological and physicomechanical properties of rod milling sand-based cemented paste backfill modified by sulfonated naphthalene formaldehyde condensate

Rod milling sand(RMS)—a coarse sand aggregate—was recycled for cemented paste backfill(CPB)for the underground mined area at the Jinchuan nickel deposit,named rod milling sand-based cemented paste backfill(RCPB).The adverse effects of coarse particles on the transportation of CPB slurry through pipelines to underground stopes resulting in weakening of the stability of the backfill system are well known.Therefore,sulfonated naphthalene formaldehyde(SNF)condensate was used for the performance improvement of RCPB.The synergistic effect of solid content(SC),lime-to-sand ratio,and SNF dosage on the rheological and physicomechanical properties,including slump,yield stress,bleeding rate,uniaxial compressive strength(UCS),as well as mechanism analysis of RCPB,have been explored.The results indicate that the effect of SNF on RCPB performance is related to the SNF dosage,lime-to-sand ratio,and SC.The slump of fresh RCPB with 0.1wt%-0.5wt%SNF increased by 2.6%-26.2%,whereas the yield stress reduced by 4.1%-50.3%,indicating better workability and improved cohesiveness of the mix.The bleeding rate of fresh RCPB decreased first and then rose with the increase of SNF dosage,and the peak decrease was 67.67%.UCS of RCPB first increased and then decreased with the increase of SNF dosage.At the optimal SNF addition ratio of 0.3wt%,the UCS of RCPB curing for 7,14 and,28 d ages increased by 31.5%,28.4%,and 29.5%,respectively.The beneficial effects of SNF in enhancing the early UCS of RCPB have been corroborated.However,the later UCS increases at a slower rate.The research findings may guide the design and preparation of RCPB with adequate performance for practical applications.

Advances of manganese-oxides-based catalysts for indoor formaldehyde removal

Formaldehyde(HCHO)has been identified as one of the most common indoor pollutions nowadays.Manganese oxides(MnO_(x))are considered to be a promising catalytic material used in indoor HCHO oxidation removal due to their high catalytic activity,low-cost,and environmentally friendly.In this paper,the progress in developing MnO_(x)-based catalysts for HCHO removal is comprehensively reviewed for exploring the mechanisms of catalytic oxidation and catalytic deactivation.The catalytic oxidation mechanisms based on three typical theory models(Mars-van-Krevelen,Eley-Rideal and Langmuir-Hinshelwood)are discussed and summarized.Furthermore,the research status of catalytic deactivation,catalysts’regeneration and integrated application of MnO_(x)-based catalysts for indoor HCHO removal are detailed in the review.Finally,the technical challenges in developing MnO_(x)-based catalysts for indoor HCHO removal are analyzed and the possible research direction is also proposed for overcoming the challenges toward practical application of such catalysts.

Factor Affecting Gel Time/Process-Ability of Urea Formaldehyde Resin Based Wood Adhesives

Urea-formaldehyde (UF) resin presents the most utilized adhesive system in the manufacture of plywood, particleboard and fiberboard. At the temperatures above 100°C in the presence of hardener, this resin undergoes cross-linking reaction and the formation of three dimensional cross linked structures takes place and bonding of wood particles in a hot press [1]. UF powder resins show high reactivity and good performance in the production and by their low price;however they lack in water resistance of the hardened resin [2]. Urea-formaldehyde (UF) resins are the most important type of adhesive resins for the production of wood based panels but process-ability and curing behavior of urea formaldehyde resin depended on various factors related to resin properties, types of wood and their properties, amount & type of catalyst, types and amount of polymers addition and environmental conditions [3]. This factor decides the process-ability of UF resin based composite during manufacturing of plywood, particle board and fiberboard. In this review paper, various factors affecting gel time and process-ability of UF resin based wood composite are reviewed.