蓖麻油基多元醇改性聚氨酯胶黏剂的研究

以绿色可再生的蓖麻油(CO)和甘油为原料进行酯交换,然后将其产物(P-CO)与六氢苯酐(HHPA)进行酯化反应制备了蓖麻油基多元醇(P-HHPA-CO),将P-HHPA-CO和甘油代替传统的石油类多元醇,与异氟尔酮二异氰酸酯(IPDI)在无催化剂条件下合成了环保型脂肪族聚氨酯胶黏剂,并对不同NCO/OH摩尔比制备的聚氨酯胶黏剂涂膜进行了热重分析、差示扫描量热分析、拉伸力学性能测试、剥离及剪切强度测试。结果表明,制得的P-HHPACO羟值为219mg KOH/g;当摩尔比为1.3时,聚氨酯胶黏剂涂膜的T剥离强度达到399.2N/m;摩尔比为1.5时,剪切强度达到7.1N/mm²。     

大豆油-油酸多元醇改性聚氨酯胶黏剂及其性能研究

以环氧大豆油（ESBO）、油酸（OA）为主要原料,在无溶剂无催化剂的条件下合成了环氧大豆油-油酸多元醇（P-OA-ESBO）,通过红外（FT-IR）和核磁（1H-NMR）对环氧大豆油-油酸多元醇（P-OA-ESBO）的结构进行了表征。然后以P-OA-ESBO、异氟尔酮二异氰酸酯（IPDI）、甘油为主要原料在无催化剂条件下合成了环保型包装用聚氨酯胶黏剂。利用热重分析（TGA）、差示扫描量热法（DSC）、拉伸力学性能测试、PE/OPP复合膜的剥离强度测试及剪切强度测试考察了不同R（NCO/OH）比聚氨酯胶黏剂涂膜的耐热、机械和粘接性能。结果表明：大豆油-油酸多元醇成功改性聚氨酯胶黏剂,相比于传统的大豆油基多元醇改性聚氨酯,该方法更为绿色经济环保,且当R值为1.3-1.5时合成的聚氨酯胶黏剂的力学拉伸和剪切能较好,R值在1.7时合成的聚氨酯胶黏剂剥离强度较优异,可满足PE/OPP膜的基本复合要求。     

新型增韧阻燃环氧树脂胶黏剂的研究

采用以聚氨酯（PU）增韧改性环氧树脂为基体,在其中添加两次包覆红磷作为阻燃剂,从而制备出一种新型增韧阻燃环氧树脂胶黏剂。通过对所制得胶黏剂进行力学性能测试、热失重测试（TG）以及阻燃性能测试,从而研究了聚氨酯和两次包覆红磷用量对改性环氧树脂胶黏剂性能的影响。结果表明,采用100份环氧树脂、30份聚酯型聚氨酯预聚体、15份阻燃剂,可制备出综合性能较好的增韧阻燃环氧树脂胶黏剂,剪切强度为23．2MPa,氧指数可达到30％。     

木质素基聚酯型聚氨酯胶黏剂的制备及表征

以玉米秸秆木质素、癸二酸、丙三醇、乙二醇和新戊二醇为原料制备了癸二酸系聚酯多元醇,并以其配合多亚甲基多苯基多异氰酸酯固化剂和有机铋催化剂制备了木质素基聚酯型聚氨酯胶黏剂,利用黏度和胶接强度测试以及FTIR和TG分析对所制备的聚酯多元醇及木质素基聚氨酯胶黏剂的性能进行了表征。结果表明,采用新戊二醇参与合成木质素基聚酯多元醇,可以得到液态产品,且新戊二醇含量越多,所得聚酯多元醇的黏度越小,以此制备的聚氨酯胶黏剂的胶接性能越好。以新戊二醇作为100%二元醇得到的木质素基聚酯多元醇配制聚氨酯胶黏剂,其胶接强度可达15.47MPa。红外分析表明,聚氨酯链段中引入了木质素分子。TG结果显示,所制得的木质素基聚酯型聚氨酯胶黏剂具有较好的热稳定性。     

无溶剂型双组分聚氨酯胶黏剂的固化研究

以4,4'-二苯基甲烷二异氰酸酯和聚醚多元醇为主要原料,合成了无溶剂型双组分聚氨酯胶黏剂的改性聚醚多元醇(A组分)和异氰酸酯封端聚氨酯预聚体(B组分),用DSC等方法研究了制备B组分中聚醚二醇与聚醚三醇羟基比例对聚氨酯胶黏剂固化反应动力学及剪切强度的影响。结果表明,保持A组分不变以及A/B组分比例不变情况下,随着B组分原料中聚醚三醇的增加,胶黏剂固化表观活化能和剪切强度均表现出先增大后减小的趋势,当聚醚二醇和聚醚三醇羟基摩尔比为2∶0.8时,胶黏剂粘接铝片的剪切强度出现最大值2.14 MPa,此时表观活化能为50.98k J/mol。     

碳基复合材料用耐高温胶黏剂的研制

采用耐热酚醛树脂杂化了磷酸盐胶黏剂,以纳米氧化铝、氧化锆和氧化锌为固化剂,制备了一种对C/C和C/SiC复合材料具有良好粘接性能的胶黏剂。通过不同测试温度下的剪切强度,差示扫描量热仪（DSC）,热失重（TG）以及扫描电子显微镜（SEM）探究了杂化胶黏剂的力学性能、固化行为、耐热性能以及高温下胶黏剂结构的变化。结果表明：酚醛树脂的加入,保持了耐热性能,降低了体系固化的固化温度,有效地提高了磷酸盐胶黏剂对C/C、C/SiC两种复合材料力学性能,室温下剪切强度均高于10MPa。     

大豆油-油酸多元醇改性聚氨酯胶黏剂的合成及性能

以环氧大豆油(ESBO)、改性油酸为原料,在无溶剂无催化剂的条件下,通过开环反应合成了环氧大豆油-油酸多元醇(P-OA-ESBO),通过红外(FTIR)和核磁(1HNMR)对环氧大豆油-油酸多元醇(P-OA-ESBO)的结构进行了表征。然后以P-OA-ESBO、异氟尔酮二异氰酸酯(IPDI)为原料,以绿色可再生的甘油为扩链剂,在无催化剂条件下合成了环保型包装用聚氨酯胶黏剂,不使用传统的石油类多元醇和有机锡类催化剂。利用热重分析(TGA)、差示扫描量热法(DSC)、拉伸力学性能测试、PE/OPP复合膜的剥离强度测试及剪切强度测试考察了不同R(NCO/OH)比聚氨酯胶黏剂涂膜的耐热、机械和粘接性能。结果表明,大豆油-油酸多元醇成功改性聚氨酯胶黏剂。当R值为1.3~1.5时合成的聚氨酯胶黏剂的力学拉伸和剪切能较好,R值在1.7时合成的聚氨酯胶黏剂剥离强度较优异,可满足PE/OPP膜的基本复合要求。     

阻燃环氧树脂胶黏剂的研制

采用以KH-560硅烷偶联剂包覆三聚氰胺多聚磷酸酯（MPP）为阻燃剂,以环氧树脂E-44为基体,制备阻燃环氧树脂胶黏剂。通过对所制得胶黏剂进行剪切强度测试、热失重测试以及阻燃性能测试,研究了包覆阻燃剂对环氧树脂胶黏剂力学性能、热稳定性和阻燃性能的影响。结果表明,采用包覆处理MPP为阻燃剂制备的阻燃环氧树脂胶黏剂综合性能较好,其剪切强度为19．9MPa,氧指数为31．2。最佳配方为100份环氧树脂、30份阻燃剂、30份固化剂、温度为70℃。     

环氧基多元醇改性水性聚氨酯的合成与性能研究

为提高水性聚氨酯的耐化学介质性能,使用顺酐（MA）与聚己内酯二醇反应生成顺酐聚己内酯二醇单酯（MP）,之后再与环氧树脂（E-51）反应,合成环氧基多元醇（EMP）最后以此为原料与聚己内酯二醇复配,制得环氧基多元醇改性水性聚氨酯（EWPU）。研究了不同反应,条件及 EMP用量对改性水性聚氨酯及涂膜性能的影响,通过红外光谱、粒径分析和热重分析对产物及涂膜进行了测试及表征。结果表明：通过在聚氨酯分子结构中引入具有柔性结构的环氧基多元醇,与未改性 WPU相比,所制备出的环氧基多元醇改性水性聚氨酯的耐介质性能明显提高,涂膜具有优异的柔韧性、附着力、硬度及耐热性等性能。     

透水路面用蓖麻油基无溶剂聚氨酯胶粘剂的制备及性能研究

以植物油基多元醇蓖麻油(CO)、多元醇2010A、三羟甲基丙烷(TMP)和1,4-丁二醇(BDO)为A胶羟基基团基本原料,PM200为B胶异氰酸酯基团基本原料,制备得到透水路面用无溶剂双组分聚氨酯胶粘剂,并对胶粘剂的力学性能和耐紫外老化性能进行了测试。研究结果证明:保持A胶中扩链剂的羟基物质的量总量不变,当TMP与BDO的羟基物质的量之比为1∶1时,聚氨酯胶粘剂的拉伸强度和断裂伸长率可达15.53 MPa和56.59%;在保证韧性基础上另添加0.15%气相SiO_2时,胶粘剂的拉伸强度提高至19.53 MPa。耐紫外老化性能表明,采用多元醇2010A制得的胶粘剂相比初始拉伸强度提高14%,断裂伸长率下降30%;相对于聚酯多元醇两个配方(XCPA和耐水解2010A),其力学性能较为稳定。     

BOND STRENGTH IMPROVEMENT OF POLYURETHANE ADHESIVE BY GRAFTING 2-HYDROXYETHYL METHACRYLATE ON POLYOL BACKBONE

A series of acrylated polyols were prepared by grafting 2-hydroxyethyl methacrylate (HEMA) on to polyol backbone prepared from vegetable oil fatty acid and epoxy resin. Grafting was carried out by free radical mechanism on conjugated double bond present in the polyol using benzoyl peroxide (BPO) as an initiator. Polyols and polyurethane adhesives were characterized by IR spectroscopy. Polyurethane adhesive synthesized from the modified polyols were found to provide better peel strength to styrene butadiene rubber (SBR) joints. Mode of failure was studied using Scanning Electron Microscopy (SEM). Improvement in cohesive strength of the adhesives resulted in high bonding strength. Comparative study has been carried out to determine the effect of acrylation on polyurethane adhesive by Green strength, Curing behavior, and Chemical resistance studies. Loading of 20% HEMA gave significant results. However, 15% loading of HEMA resulted in a sample with highest peel strength.     

Tailoring new architectures for polyurethanes using dendritic and hyper-branched polymers and their adhesion behavior. Part 1

Polyurethane adhesives and coatings are used for a variety of applications. The emerging dendritic and hyper-branched (HB) polymers, having three-dimensional (3D) morphology, have opened new avenues to tailor the architecture of polyurethane adhesives and coatings. The methodology followed in this study was based on partial replacement of the polyol in the isocyanate/polyol mixture with HB or dendrimer moieties having reactive functional groups. The resulting formulations were characterized and optimized with respect to adhesion properties (shear and peel strengths) using various HB and dendritic polymers. The results have shown that the incorporation of 1 to 2% (by weight) of hyper-branched polyamidoamine (PAMAM) results in shear strength increase (46 to 78%) compared to a reference formulation (no HB), following curing at room temperature. This was attributed to an increase in cross-link density. Higher concentrations of the hyper-branched polymer resulted in reduced shear strength due to plasticization. When the polyurethane was post-cured (80 °C for 5 h) to enhance diffusion of the HB, both shear and peel strengths increased by 64% and 100%, respectively, compared to the reference formulation. The simultaneous increase of shear and peel strengths is very unique to this adhesive system. This unique phenomenon is attributed to the incorporation of the 3D HB PAMAM which imparted a 3D cross-linked network architecture, as well as an energy-absorbing structure. In the case of PAMAM dendrimer, an optimum was exhibited in the concentration range of 0.05-0.1% (by weight). When the samples were post-cured a less significant increase in shear strength was observed (12-31%), compared to the HB-containing formulation. When the concentration was increased beyond the optimum a reduction in shear strength was obtained as a result of plasticization, as in the case of HB-containing formulations. It was concluded that the 3D architecture obtained by the introduction of 3D dendritic and HB polymers should lead to new directions for enhancing simultaneously the shear and peel strengths of polyurethane adhesives and coatings.     

Nanotailoring of polyurethane adhesive by polyhedral oligomeric silsesquioxane (POSS)

The development and commercialization of nanoparticles such as nanoclays (NCs), carbon nanotubes (CNTs) and polyhedral oligomeric silsesquioxanes (POSS) offers new possibilities to tailor adhesives at the nanoscale. Four types of POSS, with reactive mono-functional groups of isocyanatopropyl, glycidoxypropyl, aminoethyl and non-reactive octaphenyl, were incorporated in concentrations of 1, 3 and 5 wt% into a polyurethane (PU)-based adhesive. Thermo-mechanical bulk properties were studied using dynamic mechanical analysis (DMA). Adhesive properties were characterized in shear and peel modes. Atomic force microscopy (AFM) was used to study the nanoscale morphology. DMA measurements indicated that the neat PU possessed a glass transition temperature (T _g) of ≈ 30°C. The T _g of PU/POSS-glycidoxypropyl nanocomposite adhesive increased gradually with POSS concentration to 50°C for 5 wt%. PU/POSS-octaphenyl nanocomposite adhesive exhibited an increased T _g by 10°C for 5 wt%. The incorporation of POSS-isocyanatopropyl in the PU had no effect on the T _g. With respect to shear properties of POSS-octaphenyl-, POSS-isocyanatopropyl- and POSS-glycidoxypropyl-based PU nanocomposite adhesives, shear strength improved by 230, 178 and 137%, respectively, compared to neat PU. POSS-aminoethyl exhibited lower shear and peel strengths, while POSS-isocyanatopropyl provided the best balance of both higher shear and peel strengths compared to neat PU. It was concluded that the grafted functional group on the POSS and its reactivity with the PU network components were the decisive factors with respect to the thermo-mechanical, morphological and adhesive properties of the resulting nanocomposite adhesives. Consequently, the POSS/polyurethane based nanocomposite adhesives could be tailored for a large range of applications.     

Design of experiments for optimization a biodegrable adhesive based on ramon starch (Brosimum alicastrum Sw.)

In this work, a Central Composite Design (CCD) and Response Surface Methodology (RSM) were used to study the effect of starch content, hydrolyzing agent (NaOH) content, temperature and cooking period on peel strength and shear strength of biodegradable adhesives based on Ramon (Brosimum alicastrum Sw.) and Corn (Zea mays L.) starch. Scribe® paper was used as substrate or adherent. The CCD consisted of 36 experiments (including 12 central points). The second-order regression models of the response surface method, used to predict the response variables, exhibited a high correlation between the data obtained and the predicted data, and were thus considered reliable to optimize the mechanical properties for peel strength and shear strength of the Ramon starch adhesives. Starch content, hydrolyzing agent content and the cooking temperature of the adhesives proved to be the most significant factors affecting peel strength and shear strength of the adhesives of both the Ramon and corn starch. Moreover, the interactions of Starch-NaOH and Starch-Temperature were found to be the most significant in the adhesive properties in both adhesives. The mechanical properties (peel strength and shear strength) of both adhesives increased until reaching approximately their temperatures of gelatinization (T _{RAMON GEL} = 83 °C, T _{GEL CORN} = 72 °C). At higher temperatures, the mechanical properties of the adhesives diminished. The results of this study show that the adhesive prepared with the Ramon starch presents adhesive properties similar to those of an adhesive prepared with corn starch. This would imply that the Ramon starch is a viable alternative to substitute corn starch in industrial applications not relating to food production.     

Characterization of canola oil based polyurethane wood adhesives

A novel bio-based poly (ether ester) polyol containing both primary and secondary functional groups was synthesized from canola oil using a low cost and efficient procedure. In this work, use of the new canola oil derived polyol for the production of polyurethane (PU) adhesives was demonstrated. The canola oil based PU adhesives had similar or better adhesive properties in terms of lap shear strength than three commercial PU adhesives. The effect of NCO/OH ratio and temperature on adhesive characteristics on wood bonding was also evaluated by lap shear tests. It was found that the use of an elevated curing temperature (i.e. 100 °C), as well as optimized NCO/OH molar ratio (higher than 1.5/1.0), improved the wood adhesive properties. The overall chemical resistance of bio-based PU adhesives to cold water, acid and alkali was comparable to that of commercial PU adhesives whilst its resistance to hot water was superior.     

Preparation of polyurethane wood adhesives by polyols formulated with polyester polyols based on castor oil

The aim of this work was the synthesis of polyester polyols from renewable sources as one of the important compounds of polymeric polyurethane (PU) adhesives. The polyester polyols were synthesized by condensation polymerization of different dicarboxylic acids with castor oil and the reaction conditions were in agreement with green chemistry principles. The preparation of PU wood adhesives was carried out by the reaction of each obtained polyester polyol with 4, 4′-diphenylmethane diisocyanate (MDI). The adhesive performance was improved by mixing the obtained polyester polyols with polypropylene glycol (PPG 400) and butanediol (BD). Different NCO/OH ratios were used to obtain adhesives with appropriate properties. The structures of the synthesized polyesters and adhesives were characterized by FTIR, thermogravimetric analysis (TGA) and lap shear strength values were also determined in various conditions such as cold water, hot water, acid and alkali solutions.     

Sustainable isosorbide‐based transparent pressure‐sensitive adhesives for optically clear adhesive and their adhesion performance

A biomass‐based isosorbide acrylate (ISA) was synthesized in a one‐pot reaction at low temperature with a quite slow dropwise technique using a syringe pump. Using the ISA monomer, UV‐cured transparent acrylic pressure‐sensitive adhesives (PSAs) composed of semi‐interpenetrating networks were prepared. The effect of ISA on the adhesion performance of the resulting acrylic PSAs was investigated by changing the ISA content, while fixing the mole ratio between 2‐ethylhexyl acrylate and 2‐hydroxyethyl acrylate in the PSAs. The prepared acrylic PSAs, with ISA content ranging from 3.2 to 14.3 mol%, were evaluated in terms of 180° peel strength, probe tack, static shear testing and optical properties. Increasing the ISA content in the acrylic PSAs improved the adhesion properties, such as 180° peel strength (0.25–0.32 N/25 mm), shear holding power (0.086–0.023 mm) and probe tack (1.21–2.26 N). Dynamic mechanical analysis indicated that ISA is a good candidate monomer, playing the role of adhesion promoter and hard monomer in the acrylic PSAs. © 2017 Society of Chemical Industry     

Effect of natural and synthetic tackifiers on viscosities,adhesion properties and thermal stability of SNR and DPNR solution adhesives

Styrene-grafted natural rubber (SNR) and deproteinized natural rubber (DPNR) latexes were formulated with coumarone-indene (CI), gum rosin and petro resin (PR) tackifiers into solution adhesives with toluene as a solvent. The solution viscosities were evaluated by a Brookfield viscometer DV-II Plus with spindle No. 3. Pressure sensitive adhesives (PSAs) films were made and the adhesion properties were evaluated with loop tack, peel strength and shear strength tests. Thermal stability of the film was evaluated via Perkin-Elmer Pyris 6^TM thermogravimetric analysis at temperatures ranging from 30 to 600?°C at a heating rate of 10?°C per minute in nitrogen environment. Results indicate that as the tackifiers content increased, the solution viscosities increased with SNR/PR and DPNR/PR formulations showing the highest viscosities. Adhesion test also indicates that loop tack and peel strength of the adhesive solution increased but their shear strength decreased; increase of CI tackifier loadings conferred the highest peel strength for both SNR- and DPNR-based PSAs. Thermal analyses show that the addition of 40 phr CI tackifiers improved thermal stability of SNR adhesives based on their higher T_max and integral procedural decomposition temperature properties.     

Two‐component acrylic structural adhesive initiated by tributylborane for untreated PET adhesion

In order to improve the adhesion strength of acrylic adhesive to untreated poly(ethylene terephthalate) (PET) substrate, two‐component acrylic structural adhesives initiated by tributylborane were prepared. The effects of acrylic monomers, elastomers, decomplexers, and oligomers on the adhesion properties of two‐component acrylic structural adhesive were investigated in sequence. It is found that the shear strength on PET of adhesives toughened by acrylonitrile–butadiene–styrene copolymer and carboxyl‐terminated butadiene–acrylonitrile copolymer is higher than that of commercial adhesives Dp8010NS and Loctite 3030. A tailored oligomer was synthesized from hydroxyl propyl–terminated polydimethylsiloxane and 3‐isopropenyl‐α,α‐dimethylbenzyl isocyanate. It is also noticed that premature failure usually takes place in the lap shear test samples due to the brittleness of the acrylic adhesive, except in the sample of adhesive modified by tailored oligomer. Excellent adhesion to the PET substrate is achieved by this adhesive modified by tailored oligomer, with a lap shear strength above 11 MPa and T‐peel strength up to 5.34 N/mm. Additionally, the resulting adhesive is qualified for the structural bonding of PET materials. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46612.