双组分豆粕胶粘剂的固化粘弹性能研究

采用旋转流变仪分别研究了改性胶液、豆粕粉添加量、G试剂添加量对双组分豆粕胶粘剂粘弹性的影响。结果表明,双组分豆粕胶粘剂的固化粘弹性变化趋势不受改性胶液的影响,始终保持G'G";随着豆粕粉添加量的增加,双组分豆粕胶粘剂的粘弹性能逐渐增大,其交联产物的热稳定性在高温区域逐渐减弱;随着G试剂添加量的增大,双组分豆粕胶粘剂的凝胶固化行为逐渐增强,固化温度逐渐降低。通过UF树脂、PF树脂和双组分豆粕胶粘剂的性能对比发现,双组分豆粕胶粘剂的凝胶固化行为及胶合强度和耐水性能均近似介于UF树脂和PF树脂之间。     

亚硫酸处理双组分豆粕胶黏剂的应用性能研究

以豆粕粉为主要原料,采用常温复配手段制备双组分豆粕胶黏剂,分析了亚硫酸添加量对胶黏剂的物理性能、固化黏弹性能及其制备的胶合板胶合强度的影响,并通过FT-IR对亚硫酸处理制得的双组分豆粕胶进行了结构表征。研究结果表明：亚硫酸能够降低胶黏剂体系的黏度,且当亚硫酸添加量为6%时,双组分豆粕胶黏剂的黏度和pH值适中,红外表征显示亚硫酸的加入能够促进蛋白质水解,暴露更多的活性基团。在120~150 ℃范围内,固化交联程度较高,固化黏弹性能较优,且用其制备的三层胶合板可满足国家标准Ⅰ类和Ⅱ类胶合板的要求,胶合强度分别达到了1.02MPa(100 ℃)和1.24 MPa(63 ℃)。     

不同木质素磺酸钠对豆粕胶黏剂性能的影响

通过FTIR、元素分析、GPC对4种不同来源的木质素磺酸钠进行物理化学性质分析,并将其与水性聚酰胺协同改性豆粕胶黏剂(简称豆粕胶),利用测试接触角、剪切黏度和湿态胶合强度考察改性前后胶黏剂的浸润性、流变特性以及所得胶合板的胶合性能.红外谱图分析表明,在1065 cm–1附近出现了磺酸基或磺甲基中S==O的伸缩振动吸收峰,证明木质素经过磺化反应或磺甲基化反应得到木质素磺酸钠;木质素磺酸钠中磺酸基含量越高,经其改性的豆粕胶的零剪切黏度越低且在木材表面的润湿性越好;豆粕胶黏剂与杨木单板的接触角从未改性的95°降到改性后的61°;与水性聚酰胺协同改性后的豆粕胶制得胶合板的湿态胶合强度达到0.92 MPa,合格率为100％,满足国家Ⅱ类胶合板的标准要求(胶合强度≥0.70 MPa,合格率≥90％).     

协同交联型大豆胶黏剂的流变与固化性能研究

利用饲料级大豆粉为原料,通过水性聚酰胺和异氰酸酯对其进行协同复合改性制备出具有良好流变行为和固化性能的大豆胶黏剂。采用旋转流变仪研究了复合改性剂用量对大豆胶黏剂流变行为和固化性能的影响,结果表明：改性后的大豆胶黏剂属于假塑性流体,当水性聚酰胺添加量为10%时,所得大豆胶黏剂的流变性能较优,而异氰酸酯添加量对大豆胶黏剂的流变行为几乎没有影响;运用动态温度扫描模式研究大豆胶黏剂的黏弹性能,异氰酸酯添加量对大豆胶黏剂的储能模量和损耗模量影响较大。水性聚酰胺/异氰酸酯协同交联体系可与大豆蛋白分子间发生交联,当10%水性聚酰胺和4%异氰酸酯协同改性时,所得胶合板的胶合强度可达0.74 MPa,满足国家Ⅱ类胶合板使用要求（≥0.70 MPa）。     

长支链型高熔体强度聚丙烯流变性能的研究——剪切流变

通过辐照法制备了长支链型高熔体强度聚丙烯（LCB-HMSPP），采用高级流变扩展系统（ARES）表征了其熔体黏弹性，采用毛细管流变仪研究了其在高剪切速率下的流变行为。讨论了敏化剂用量、超高相对分子质量聚乙烯（PE-UHMW）对PP熔体黏弹性、流动曲线和黏流活化能的影响。动态剪切流变数据表明，辐照改性制备的LCBHMSPP具有较好的熔体黏弹性，并且其熔体弹性随敏化剂用量的增加而增强，表现在低频端剪切储能模量明显提高，内耗正切变小，零切黏度增大，特征松弛时间变长；辐照过程中添加极少量PE-UHMW也可提高PP的熔体黏弹性。静态毛细管剪切流变测试表明，线形PP和长支链PP的流动曲线较相似，LCB-HMSPP的黏流活化能较线形PP有显著提高，其剪切黏度具有较高的温度敏感性。     

丙烯酰胺黄原胶接枝共聚物水溶液粘性行为研究

以丙烯酰胺（AM）、黄原胶（XG）为主要原料,硝酸铈铵（CAN）为引发剂,合成了丙烯酰胺黄原胶接枝共聚物（XGA）,研究了无机盐（NaCl、CaCl2、MgCl2）浓度、温度、老化时间和剪切速率等因素对XGA溶液黏性行为的影响。结果表明,XGA具有与XG相同的优良的耐盐性能,XGA溶液的黏度在高温（85℃）下具有更好的时间稳定性;XG和XGA溶液的流变曲线均表现为宾汉流体的流变行为,当剪切速率由最大值逐渐减小时,溶液黏度逐渐恢复,但与初始黏度相比存在滞后现象。     

SBS溶剂型胶黏剂黏度的控制

SBS溶解性好,可与很多聚合物相容,非常适宜制备溶剂型胶黏剂。苯、甲苯、二甲苯是SBS树脂的良溶剂,但毒性大,故为SBS树脂选用LD50〉5000mg／kg的无毒溶剂-丙酮、乙酸乙酯和汽油调配混合溶剂。SBS弹性体本身并无粘接性,必须配合适当的增黏树脂改性。黏度是胶黏剂的重要技术指标。研究了汽油、丙酮和乙酸乙酯混合溶剂组分对黏度的影响。讨论了增黏树脂及其混合体系对黏度的影响。研究了增黏树脂含量和固含量对黏度的影响。结果表明,乙酸乙酯含量高,黏度低;添加增黏树脂混合体系比添加单一增黏树脂,黏度高;固含量高,黏度高;增黏树脂含量高,黏度低。乙酸乙酯含量、增黏树脂含量和固含量等是控制SBS溶剂型胶黏剂黏度的有效手段。     

双组分无溶剂聚氨酯胶黏剂的制备及性能研究

以聚醚多元醇和二苯基甲烷二异氰酸酯为原料,通过聚合反应制得双组分无溶剂聚氨酯胶黏剂的A组分;分别以蓖麻油、聚醚多元醇、聚酯多元醇、蓖麻油改性的聚酯多元醇作B组分。将A、B组分混合,涂布于复合膜之间,经熟化反应,制得双组分无溶剂聚氨酯胶黏剂。系统研究了A组分中的异氰酸酯基含量、B组分多元醇种类对胶黏剂的黏结强度和耐水煮性能的影响。结果表明：当A组分异氰酸酯基质量分数为17%时,胶黏剂的剥离强度最大;采用蓖麻油改性的聚酯多元醇作B组分时,胶黏剂黏结性能优异,经沸水煮3 h后,其剥离强度维持在3.7×15^-1N/mm,展现出优异的耐水煮性能。     

有机锆交联羟丙基瓜胶流变动力学

以乳酸/丙三醇有机锆为交联剂,羟丙基瓜胶为稠化剂,研究了羟丙基瓜胶凝胶的流变性(黏弹性、触变性)及其交联流变动力学,获得了羟丙基瓜胶交联过程中黏度、黏弹性模量随时间的变化关系,并考察了剪切速率和温度对凝胶形成的影响,建立了交联流变动力学模型。结果表明,交联羟丙基瓜胶凝胶具有明显的黏弹性和触变性;一级交联流变动力学模型可描述羟丙基瓜胶的交联流变动力学过程,模型参数物理意义明确合理。     

乳胶粉掺量对纤维素醚改性水泥浆体流变性能的影响

采用Anton Paar MCR 302型流变仪研究了乳胶粉掺量对纤维素醚改性水泥浆体流变性能和触变性的影响.结果表明,掺入乳胶粉的纤维素醚改性水泥浆体表现为剪切稀化的流变特性,当剪切速率较小时,浆体黏度下降显著.乳胶粉掺量越大,浆体基于Herschel-Bulkey模型拟合得到的屈服应力和黏度系数均越大.并且乳胶粉能...     

Rheological behavior of anaerobic adhesives: Rheological profile modelling depending on the composition

A study is done on the influence of fumarate-based thickeners on the rheological behavior of low-molecular-weight poly(ethylene glycol) dimethacrylate monomers diluents, often used as major components in the formulation of anaerobic adhesives. These solutions generally showed pseudoplastic behavior. The Cross equation was selected to determine the viscosity vs. shear rate curves, at constant temperature. The final equation relates the viscosity as a function of shear rate and thickener concentration. In addition, the zero shear rate viscosity evolution as a function of the thickener weight fraction was studied, showing that two critical concentrations were present.     

Soy proteins as plywood adhesives: formulation and characterization

Soybean proteins have great potential as bio-based adhesives. The objectives of our study were to develop and characterize formaldehyde-free soybean wood adhesives with improved water resistance. Second-order response surface regression models were used to determine the effects of soy protein isolate concentration, sodium chloride, and pH on adhesive performance. All three variables affected both dry and wet strengths of bonded wood specimens. The optimum operation zone for preparing adhesives with improved water resistance is at a protein concentration of 28% and pH 5.5. Sodium chloride had negative effects on adhesive performance. Soy adhesives modified with 0.5% sodium chloride had dry strength, wet strength, and boiling strength of bonded specimens comparable to nonmodified soy adhesives. Rheological study indicated that soy adhesives exhibited shear thinning behavior. Adhesives modified with sodium chloride showed significantly lower viscosity and yield stress. Sodium chloride-modified soy adhesives formed small aggregates and had low storage moduli, suggesting reduced protein–protein interactions. These formaldehyde-free soy adhesives showed strong potential as alternatives to commercial formaldehyde-based wood adhesives.     

Effect of ball-milling parameters on the rheological properties of mold powder slurry

In this study, mold powder slurries with high solid loading and low viscosity were prepared during the ball-milling process for improving the homogeneity and mechanical properties of granules after spray-drying. The effect of ball-milling parameters, such as solid loading, binder/dispersant content, and ball-milling time, on the flowability, dispersibility, stability, and rheological behavior of mold powder slurries was systematically investigated by rheology observation and sedimentation tests. As these parameters varied, the slurry exhibited the shear-thinning behavior of a non-Newtonian fluid with a shear rate range of 0–50 s^?1, which was adequately described by the Herschel-Bulkley model. The optimal parameters that optimized the flowability, dispersibility, and stability of the slurry, along with its rheological behavior, were chosen as follows: solid loading, 60 wt%; modified sodium carboxymethyl cellulose binder content, 1.0 wt%; sodium tripolyphosphate dispersant content, 0.5 wt%; ball-milling time, 60 min.     

超细粉体对水泥净浆流变行为影响研究

采用截锥圆模法测定不同掺量超细粉体水泥复合浆液的流动度.采用ZNN-D6B型旋转黏度计研究超细玻璃粉和偏高岭土两种超细粉体对水泥净浆流变行为的影响,得到了剪切速率-剪切应力(γ-τ)曲线和剪切速率-表观粘度(γ-μa)曲线,并分别采用宾汉姆模型和赫-巴模型对γ-τ流变曲线进行拟合,得到不同掺量超细玻璃粉-水泥(GP-C)复合浆液和偏高岭土-水泥(MK-C)复合浆液的动切力、塑性粘度、稠度系数和流性指数等流变参数.结果表明:超细粉体的加入降低了复合浆液的流动度.随着掺量的增加,两种复合浆液的宾汉动切力τ0、塑性粘度η、赫-巴动切力τy均逐渐增大,MK-C复合浆液的稠度系数K和流性指数n逐渐减小,GP-C复合浆液的稠度系数K呈现增大-减小-增大的趋势,而流性指数n呈现减小-增大-减小的趋势.所有样本表观粘度μa都随着剪切速率的增大而减小,呈现剪切稀释现象.     

Rheological Study of Vegetable Oil Based Hyperbranched Polyurethane/Multi-Walled Carbon Nanotube Nanocomposites

Hyperbranched polyurethanes [HBPUs] and vegetable oil based polymer nanocomposites have been drawing an imperative attention for their plentiful advantages across a spectrum of potential applications. This study divulges the rheological behaviors of Mesua ferrea L. seed oil modified HBPU/multiwall carbon nanotube [MWCNT] nanocomposites prepared by in-situ technique. Rheological phase transition behavior was studied at 120°C in the steady shear and oscillation mode. The nanocomposites showed shear thinning behavior in both the modes. The rheological characteristics were dependent on the loading of the nanotube as confirmed from this study. The storage and loss moduli values were higher than the pure HBPU and they showed improved viscosity by nanocomposite formation. The nanocomposites revealed a pseudo–solid-like behavior at relatively low frequencies. The effects of temperature on storage and loss modulus have also been explored. The temperature dependence complex viscosity further described the ease of processibility. It has been tried to establish a structural property relationship of the systems from rheological study.     

Rheological behavior of zirconia feedstock flowing through various channels considering wall-slip

The existence of wall slip for ZrO₂ feedstock flow in micro powder injection molding was investigated based on capillary rheometer experiments using dies of three dimensions. A power law function was derived by data fitting to determine the wall slip velocity based on which numerical simulation was carried out to explore the influence of wall slip on micro injection molding. Experimental results indicate that the feedstock is less sensitive to temperature fluctuation at higher shear rates. Power-law model can provide higher accuracy than the modified Cross model to depict the rheological behavior of the feedstock in capillary flows with different channels. Numerical simulation results show that in case of steady flow higher dynamic viscosity of the feedstock and higher pressure losses of the flow appeared when the wall slip boundary was included as compared to no-slip assumption in micro powder injection molding. This is because that when the wall slip boundary was included the shear rate distribution of the feedstock was lower than that of the feedstock assuming no-slip boundary.     

Adhesion strength of sodium dodecyl sulfate-modified soy protein to fiberboard

Thermal and rheological properties of sodium dodecyl sulfate (SDS)-modified soy protein isolate (SPI) adhesives were studied using differential scanning calorimetry (DSC) and rheometry. The ordered structure of native SPI was denatured as SDS concentration increased, and thermal stability of native SPI decreased at high SDS concentration. The enthalpy of SPI denaturation decreased significantly with increasing SDS concentration. Apparent viscosity of the SPI adhesives increased as SDS concentration increased. The SPI adhesives modified by high concentrations of SDS exhibited characteristics of a Newtonian-type flow. The SDS-modified SPI adhesives were applied to fiberboard, and effects of SDS concentration, press conditions, and assembly time on bond strength were investigated. Shear strength of the SPI adhesives increased with SDS concentration, reaching its maximum value at 3 wt% of SDS, and then decreased significantly. The shear strength increased as press time and/or press temperature increased. High press temperature (100 °C) and long press time (5 min) are needed to achieve relatively good adhesion properties. The shear strength also increased as assembly time increased. The shear strength of the SDS-modified SPI adhesives decreased after soaking in water for 24 h.     

混合酸水解法合成新型改性骨胶及性能研究

采用混合酸(盐酸和柠檬酸)水解、戊二醛共聚交联等手段,对传统骨胶进行改性。以混合酸中柠檬酸的体积分数、水解温度、水解时间以及戊二醛用量作为试验因素,改性骨胶黏度和凝固点作为考核指标,采用单因素试验法优选出制备改性骨胶的最佳工艺条件。结果表明:当m(骨胶)=25 g、V(水)=25 mL时,改性骨胶的最佳工艺条件为25 mL混合酸中φ(柠檬酸)=0.06%、酸解温度65℃、酸解时间35 min和V(0.5%戊二醛)=1.5 mL;由最佳工艺条件制成的改性骨胶黏合剂,其凝固点为-2℃、黏度为1 850 mPa·s、剪切强度为1.87 MPa、开胶时间为1.5 h、适用期为90 d且具有良好的热稳定性能。     

茂金属聚乙烯蜡对PE共混体系流变行为的影响

用毛细管流变仪研究了茂金属聚乙烯蜡改性聚乙烯共混体系的流变行为，探讨了茂金属聚乙烯蜡用量对共混体系熔体流变行为、熔体黏度、非牛顿指数和流动活化能的影响。结果表明：茂金属聚乙烯蜡对LLDPE／LDPE流动黏度降低明显，增加用量可使黏度逐渐降低；而对MPE／LLDPE／LDPE共混体系流动行为的影响比较复杂，在低剪切应力下黏度随茂金属聚乙烯蜡用量增加而逐渐降低，而在高剪切应力下黏度先增后减；茂金属聚乙烯蜡与MPE／LLDPE／LPDPE的相容性好于LLDPE／LDPE共混体系。     

Modified tapioca starch as a rheology modifier in acrylic dispersion system

Tapioca starch was modified by esterification reaction using octenylsuccinic anhydride (OSA) to use as a rheological modifier. Effect of degree of substitution (DS = 0.01–0.04) of octenyl side chain on rheological properties of modified starch in acrylic dispersion system (ASD) was investigated. At low starch to dry acrylic ratio (0.2:100), shear viscosity at low shear rate of OSA-starch containing ASD system increased when the DS of OSA-starch increased. Thickening ability and thixotropic behavior of modified starches in acrylic dispersion system were studied at various modified starches to dry acrylic ratios (0.1–4:100). The results showed that modified starches provided good thickening efficiency. Moreover, an optimum concentration of modified starches, giving the highest thickening efficiency decreased as the DS increased. Results of rheological behavior illustrated that associative networks were formed by hydrophobic interaction between octenyl side chains and acrylic particles in acrylic dispersion system. The rheological properties of modified starches prepared in this study showed a potential in using as an associative thickener in water-based coating system.