封闭型异氰酸酯对碱降解大豆蛋白胶粘剂的交联改性

以Na HSO3(亚硫酸氢钠)封闭的PAPI(多苯基多甲基多异氰酸酯)作为化学交联剂,对DSP[碱降解改性SPI(大豆分离蛋白)]进行交联改性,制得工艺操作性能良好的胶合板用改性SPI胶粘剂。研究结果表明:Na HSO3能封闭PAPI中的活性—NCO基团,从而延长了改性SPI胶粘剂的适用期(为2~5 h);封闭型PAPI能提高改性SPI胶粘剂的耐水性,其湿态胶接强度(0.8~1.0 MPa)满足国家标准中II类胶合板的使用要求;当w(封闭型PAPI)=15%(相对于DSP质量而言)、w(Na HSO3)=0.4%(相对于PAPI质量而言)时,改性SPI胶粘剂具有相对最佳的工艺操作性能和耐水性。     

三聚氰胺添加方式对胶合板用UF胶粘剂性能的影响

以聚乙烯醇(PVA)和三聚氰胺为改性剂,制备出一种环保型UF(脲醛树脂)胶粘剂。探讨了三聚氰胺的添加方式(包括其添加量、初期和中期投入比例等)对UF性能的影响。结果表明:在试验工艺条件下,当w(总三聚氰胺)=6%(相对于尿素质量而言)、w(前期三聚氰胺)=1%和w(中期三聚氰胺)=5%时,胶合板的甲醛释放量(0.27 mg/L)相对最低,胶接强度(0.71 MPa)达到II类板的标准要求;当w(前期三聚氰胺)=w(中期三聚氰胺)=3%时,胶合板的胶接强度(0.76 MPa)相对最高,但甲醛释放量(0.56 mg/L)只能达到E1级标准要求。     

异氰酸酯乳液胶粘剂的制备及应用

以脂肪酸与聚乙二醇单甲醚(MPEG)为原料,通过酰氯化反应合成了一系列的可乳化多亚甲基多苯基多异氰酸酯(PAPI)的非离子型乳化剂。通过核磁共振氢谱(~1H-NMR)确定合成的乳化剂分子结构,并通过激光粒度仪表征所制备乳液的粒径及其分布。通过丙酮-二正丁胺化学滴定分析法表征乳液中异氰酸酯基活性含量,最后将制备的乳液应用到胶合板,对剪切强度进行测试分析。研究结果表明:该异氰酸酯乳液中w(PAPI)=15%时,胶合板性能达到国家标准要求(Ⅱ类板);并且当w(PAPI)=20%时,胶接强度较好,Ⅱ类板湿强和Ⅰ类板湿强分别为1.22和0.93 MPa。     

淀粉与脲醛树脂复合胶粘剂的制备与性能研究

以聚乙烯醇(PVA)、硼砂、玉米淀粉、次氯酸钠、亚硫酸钠和纳米高岭土等为主要原料,制备淀粉胶粘剂;然后以常温固化的UF(脲醛树脂)作为淀粉胶粘剂的交联改性剂,制备UF/淀粉复合胶粘剂。研究结果表明:当w(PVA)=10%、m(硼砂)∶m(干淀粉)=12.5∶30、w(纳米高岭土)=2%和m(淀粉胶)∶m(UF胶)=5∶5时,相应复合胶粘剂的综合性能(包括流动性、耐水性和干湿胶接强度)相对最佳。     

聚丙烯酸钠改性淀粉标签胶的研究

以玉米淀粉、聚乙烯醇(PVA)和聚丙烯酸钠为主要原料,过氧化氢为氧化剂,氢氧化钠(Na OH)为糊化剂,硼酸为交联剂,水为溶剂,制备了一种性能优良的玉米淀粉标签胶。研究结果表明:当w(水)=60%、w(玉米淀粉)=4.5%、w(聚丙烯酸钠)=0.5%、w(过氧化氢)=0.25%、w(PVA)=15%、w(硼酸)=0.005 7%和w(Na OH)=0.16%(均相对于胶液总质量而言),并加入适量的氯化钙、三聚磷酸钠、尿素、乙醇、苯酚和消泡剂时,合成的淀粉标签胶呈乳白色果冻状黏稠液体,黏度为80 Pa·s,并且能够满足啤酒瓶高速贴标的生产要求。     

玉米淀粉的氧化工艺对改性低毒脲醛树脂性能的影响

为了进一步降低胶合板中的游离甲醛释放量和提高其胶接强度,采用湿法自制的氧化玉米淀粉对胶合板用低毒脲醛树脂(UF)胶粘剂进行改性。通过改变氧化体系的酸碱性、氧化时间以及氧化淀粉用量,优选出制备改性UF胶粘剂的较佳工艺条件。结果表明:在碱性条件下将玉米淀粉氧化40 min,然后将其作为UF胶粘剂的改性剂,当w(氧化淀粉)=15%(相对于尿素质量而言)时,改性UF胶粘剂的综合性能较好。     

复合改性淀粉基木材胶粘剂的制备

首先糠醛和聚乙烯醇(PVA)在酸性条件下合成聚乙烯醇缩糠醛树脂;然后将该树脂和环氧氯丙烷对氧化淀粉进行2步改性,并加入适量的亲水改性多异氰酸酯,制得多层人造板用淀粉基木材胶粘剂。研究结果表明:当pH为10、w(聚乙烯醇缩糠醛树脂)=20%和w(环氧氯丙烷)=1.0%(均相对于氧化淀粉胶粘剂质量而言)时,该胶粘剂的湿态剪切强度升至0.68 MPa;施胶前加入3.0%亲水改性多异氰酸酯(相对于氧化淀粉胶粘剂质量而言),则该胶粘剂的胶接强度(为0.72 MPa)满足GB/T 9846—2004标准中Ⅱ类胶合板的指标要求。     

氧化淀粉交联改性PVA胶粘剂的制备和性能研究

以聚乙烯醇(PVA)和红薯淀粉为原料、硼砂为交联剂、双氧水(H2O2)和过硫酸铵(APS)为氧化剂,采用氧化交联法制备了环保、耐水和高强的氧化淀粉交联改性PVA胶粘剂。研究结果表明:淀粉和PVA之间发生了氧化反应,并形成了交联结构;当w(淀粉)=40%、w(H2O2)=3%、w(APS)=0.45%和w(硼砂)=2.0%(均相对于PVA质量而言)时,改性胶粘剂的综合性能相对最好,其胶接强度、耐水性分别为0.88 MPa、95 h,并且其流动性好、无霉变现象。     

玻璃基材用聚氨酯底涂剂的合成与性能研究

以聚碳酸酯多元醇为主要原料制备聚氨酯预聚体(P-P),后按不同比例加入多亚甲基多苯基多异氰酸酯(PAPI)、多官能硅烷偶联剂等助剂,通过溶液聚合法合成出一种用于汽车挡风玻璃安装的湿固化型底涂剂,并探讨了预聚体、PAPI、硅烷偶联剂对底涂剂剪切强度和表干时间的影响。研究结果表明:当w(预聚体)=15%、_w(PAPI)=3%和w(硅烷偶联剂T)=10%(均相对于底涂剂总质量而言)时,制备的底涂剂综合性能相对最佳;使用底涂剂后剪切强度相对最高可达1.40 MPa,且经过耐老化处理后的破坏形式为完全内聚破坏,可满足实际生产要求。     

改性大米淀粉胶粘剂的制备和应用

以大米淀粉为原料、丙烯酰胺(AM)为接枝改性剂、封闭型异氰酸酯为主交联剂和三羟甲基苯酚(TMP)为助交联剂,合成了一种改性大米淀粉胶粘剂。对各种影响因素进行了分析,得出了最佳的工艺参数,即当w(淀粉)≈25%(相对于主剂而言)、w(双氧水)=7%(相对于淀粉而言)、6%≤w(AM)≤8%(相对于主剂而言)、w(TMP)=5%(相对于主剂而言)、并选用乙烯/醋酸乙烯共聚乳液(VAE)作为分散剂以及采用亚硫酸氢钠对芳香族异氰酸酯预聚体进行封闭时,改性大米淀粉胶粘剂的耐水性能和胶接性能明显提高,符合Ⅱ类胶合板的使用要求。     

快速固化汽车顶棚胶的研制

以二丁基二月桂酸锡为促进剂,多异氰酸酯PAPI与聚醚220反应制得单组分溶剂型聚氨酯胶黏剂,用于汽车内饰材料与车体的粘接.首先考察了PAPI用量、促进剂用量对粘接性能的影响,试验结果表明PAPI及促进剂用量较高时粘接效果好.探讨了不同处理方法对胶黏剂黏度及贮存性能的影响,发现加入苯甲酰氯后胶黏剂的黏度低、贮存过程中黏度变化小.通过对胶黏剂贮存期、适用期的考察表明其贮存稳定、工艺性能好,适合流水线喷涂作业.     

以聚乙烯醇接枝玉米淀粉为主剂的API胶粘剂

介绍了一种不含甲醛的聚乙烯醇接枝玉米淀粉胶粘剂的合成方法,探讨了改性机理,对聚乙烯醇与玉米淀粉的配比、次氯酸钠的用量、过硫酸钾的用量等影响胶粘剂性能的因素,以及主剂与交联剂PAPI的配比进行了讨论,该胶粘剂可代替脲醛树脂作为木材、胶合板用胶粘剂。     

高取代度乙酰淀粉在改性聚醋酸乙烯酯乳液中的应用研究

在改性聚醋酸乙烯酯(PVAc)乳液中添加高取代度乙酰淀粉,研究了乙酰淀粉的取代度和用量对乳液性能的影响,确定了相对较佳的配比方案。然后由改性PVAc乳液、高取代度的乙酰淀粉和助剂等制取一种耐水性好、环保和低成本的水性高分子异氰酸酯(API)胶粘剂的主剂,并以多苯基多亚甲基多异氰酸酯(PAPI)为固化剂,制取API木材胶粘剂。按照GB/T9846-2004标准对单板施胶并压制三层胶合板,则胶合板的湿胶合强度(超过1.7MPa)和甲醛释放量(0.0143mg/L)完全符合GB/T9846-2004标准中的指标要求。     

玉米淀粉改性API胶研究

先对玉米淀粉酯化制成玉米淀粉乳液,然后再用玉米淀粉改性水性高分子异氰酸酯胶(API)。即在一定条件下与玉米淀粉,碳酸钙,多异氰酸酯(PAPI)和丁苯胶乳相混合,搅拌均匀,调制成玉米淀粉胶粘剂, 压制三层胶合板,其性能完全达到有关标准要求,并且制品无甲醛无毒害物质挥发,原料成本也很低,具有明显的社会环境效益和经济效益。     

木材用单组分湿固化聚氨酯胶粘剂的合成

以多亚甲基多苯基多异氰酸酯(PAPI)、聚丙二醇(PPG-N210)和催化剂2,2'-二吗啉二乙基醚(DMDEE)为主要原料合成了一种木材用单组分湿固化聚氨酯胶粘剂,分析了NCO含量、催化剂用量、扩链系数对胶粘剂性能的影响,并与国内外木材用胶粘剂进行了比较。结果表明,NCO质量分数为12.3%、催化剂用量为0.1%、扩链系数为0.2,制得的胶粘剂室温固化且固化速度快,粘接性能较好,适合于木材的粘接。     

Enhanced performance of urea–glyoxal polymer with oxidized cassava starch as wood adhesive

To eliminate the hazard of formaldehyde from wood-based products to human and environment, formaldehyde was replaced by glyoxal to produce wood adhesive. Urea–glyoxal (UG) resin was environmental friendly, while its bonding strength was very poor, especially its water resistance. The object of this work was to improve the mechanical properties of UG resin by oxidized cassava starch addition. Hence, the urea–glyoxal (UG) resin was synthesized and the oxidized cassava starch was added through mechanical mixing. The bonding strength, structure distributions, and the morphology features of the cured UG resin system were investigated by producing a three-layer plywood, FTIR, and SEM analysis. The results of dry and wet shear strength of plywood indicated that there was a positive effect of oxidized cassava starch on bonding strength of a three-layer plywood, and when the oxidized cassava starch content was increased to 45%, the dry strength could reach 1.21 MPa, and the wet strength was 0.72 MPa. The FTIR results showed that chemical reaction between UG resin and oxidized cassava starch was beneficial to the branched structure formation and higher cohesion strength of UG resin. Meanwhile, the tightness structure of enhanced UG resin system was observed by SEM analysis as well. These improved properties were contributed to water resistance improvement of UG resin.

     

氧化条件对淀粉/丙烯酸共聚物粘接性能的影响

以双氧水(H2O2)为氧化剂、硫酸铜(CuSO4)为氧化催化剂,玉米淀粉经氧化、糊化和AA(丙烯酸)接枝改性后,制得淀粉/AA接枝共聚物;然后以此为瓦楞纸板生产用淀粉胶粘剂的载体,以淀粉氧化过程中的pH、催化剂含量、氧化剂含量、氧化时间和氧化温度为试验因素,以接枝淀粉胶粘剂/瓦楞纸板的粘接强度和边压强度为考核指标,采用单因素试验法优选出制备该胶粘剂的最佳工艺条件。结果表明:当pH=10、V(0.1 mol/L CuSO4)=0.6 mL、w(H2O2)=0.6%、氧化时间为20 min和氧化温度为30℃时,接枝淀粉胶粘剂具有相对最好的粘接性能,相应接枝淀粉胶粘剂/瓦楞纸板的粘接强度和边压强度相对最大。     

Thermal, mechanical, and rheological properties of poly(propylene carbonate) cross-linked with polyaryl polymethylene isocyanate

In this study, cross-linked poly(propylene carbonate) (PPC) was prepared using polyaryl polymethylene isocyanate (PAPI) as a cross-linking agent. The gel content, thermal behaviors, mechanical and rheological properties of the cross-linked PPC were investigated. FTIR results showed that the chemical reactions took place between PPC and PAPI and the interactions demonstrated that PPC may be cross-linked with the PAPI. The results of gel content revealed that PPC was partially cross-linked with the PAPI. The cross-linked PPC showed higher glass transition temperature and decomposition temperature compared with pure PPC. Accordingly, the melt flow index gradually decreased and complex viscosity increased with increasing PAPI content. Moreover, the mechanical properties proved also to be enhanced as evidenced by tensile tests. The introduction of small amount of cross-linkable moiety provides an efficient and convenient method to improve the properties of PPC and extend its application area.     

Study on cross-linking agent of a novel one-component API adhesive

The high reactivity and toxicity of isocyanates do not allow their storage and use in one-component system aqueous polymer isocyanate adhesives. Blocked isocyanates are a solution to protect the isocyanate groups by blocking with suitable blocking agent. In order to obtain eco-friendly systems and eliminate the effect of the organic solvents on environment, the blocked isocyanates can be dispersed in water by using external emulsifier by incorporating hydrophilic groups into the backbone. In this work, a series of waterborne blocked polyisocyanate dispersions were prepared by anionic modified process, using polyaryl polyisocyanate (PAPI), 2,4,6-trichlorophenol (TCP), and dimethylol propionic acid. Particle sizes were measured and compared by laser particle sizer and scanning electron microscopy. The structures of aqueous dispersions were characterized by FTIR, ¹H NMR, and ¹³C NMR, and results confirmed that the –NCO groups are effectively blocked by –OH groups. Thermal property was investigated using differential scanning calorimetry; then, kinetic parameters, ΔE, and n were deduced. It was found that the deblocking temperature of aqueous dispersion is about 55?°C. Hydrophilicity was characterized by measuring the water contact angles. The experimental results showed that the contact angle of solvent-borne solution is 68.6°, while that of aqueous dispersion is only 25.2°, which indicated that the hydrophilicity of waterborne TCP-blocked PAPI increases for the introduced hydrophilic group compared with solvent-borne TCP-blocked PAPI. The compressive shear strength was tested to evaluate wood bonding performance of the adhesive.     

TM体系在普通聚氨酯软泡中的应用研究

以TDI-65与PAPI按一定比例混合(TM体系)为原料,制取普通聚氨酯软泡。讨论了催化剂、表面活性剂和PAPI对泡沫的影响,并分析了经济效益。实验表明,以TM体系代替TDI-80制备普通聚氨酯软泡,与同类普通软泡比较,具有综合物理性能高、成本低的优点,有很高的开发和应用价值。