共查询到20条相似文献,搜索用时 15 毫秒
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MUF共缩合树脂的研制 总被引:1,自引:0,他引:1
为缓解苯酚紧缺,进行了用三聚氰胺改性脲醛树脂(MUF树脂)取代酚醛树脂生产室外级胶合板的研究。考查了三聚氰胺用量、反应工艺条件及增粘剂对MUF树脂性能的影响。抽样做胶合板耐候性试验表明,MUF树脂可取代酚醛树脂。 相似文献
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研究了聚乙烯醇和三聚氰胺改性脲醛树脂胶粘剂的制备工艺和配方。以尿素和甲醛为单体,添加适量三聚氰胺和聚乙烯醇改性剂,甲醛和尿素最佳物质的量比为1.5∶1,尿素分3次投料,反应温度控制在85℃左右,反应时间60 min,可制得综合性能较好的低毒耐水脲醛树脂胶粘剂。产品固含量>60%,黏度(涂-4)120~150 s,剪切强度可达2.93 MPa,耐沸水时间可达122 min,游离甲醛质量分数可降至0.026%,产品质量完全达到国家规定的指标[1]。 相似文献
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This study compared the effect of different adhesive systems and composite resins on the shear bond strength (SBS) of repaired high-viscosity bulk-fill composites(Tetric EvoCeram Bulk Fill) and investigated failure modes. One hundred twenty cylindrical bulk-fill composite blocks (diameter 5?mm) were fabricated and thermocycled for 5000 cycles (5–55?°C). Specimens were roughened by diamond bur and divided into 8 groups (n?=?15). Bulk-fill blocks were repaired with the same material or nanohybrid composite resin(Tetric EvoCeram Nanohybrid) (diameter 3?mm) using different adhesive systems:Tetric N-Bond Universal (TSE);37% phosphoric acid etching?+?Tetric N-Bond Universal (TER); Clearfil SE Bond (CSE); 37% phosphoric acid etching?+?AdperTMSingle Bond 2(SB). After repair procedures, all specimens were thermocycled again. The shear bond strengths were measured for all specimens using a universal test machine (crosshead speed of 1?mm/min). Cohesive strengths of bulk-fill composites were measured and described as control group. Debonded surfaces were observed with a stereomicroscope under 10x magnification to determine mode of failure. The SBS data of all groups was statistically analyzed by two-way ANOVA and Bonferroni correction test (p?<?0.05). The specimens repaired with bulk-fill composites showed significantly higher SBS values (25.86?±?5.74, 27.05?±?4.93, 24.49?±?6.95MPa) than those with nanohybrid composites (20.41?±?3.70, 22.08?±?6.37, 18.74?±?6.40?MPa) for TER,CSE,SB, respectively (p?<?0.05). There were no significant differences in SBS according to the type of adhesive systems for both repair materials (p?>?0.05). The predominant mode of failure was a mixed type in the restorative material except for the ones repaired with nanohybrid composites using AdperTMSingle Bond 2. High-viscosity bulk-fill composites could be successfully repaired with the same materials. SBS of repaired bulk-fill composites reached cohesive strength for all tested groups. 相似文献
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环氧-聚砜结构胶粘剂耐环境性能的研究 总被引:7,自引:3,他引:4
报导了SY-14环氧-聚砜胶粘剂体系的耐环境性能研究结果。在北京、南昌、广州和海口四个不同气候条件下的10年大气曝晒试验表明,各项胶接强度均末发生明显变化。含有抑制腐蚀底胶的胶接试板进行的10年室温盐水浸泡试验也取得了优良的试验结果。 相似文献
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ABSTRACTThis study was designed to evaluate the effect of different treatments on the zirconia/resin shear bond strength (SBS) using commercial one-bottle universal adhesive. Zirconia discs with different surface treatments (blank control; airborne-particle-abrasion; glazing) were bonded to the bovine enamel surfaces using one-bottle universal adhesive. All specimens were tested for SBS (MPa) before and after 10000 thermocycles. Statistically analysis were conducted by using one-way analysis of variance and multiple-comparison least significant difference tests (α = 0.05). Airborne-particle-abrasion group showed higher SBS (36.19 ± 11.86) than control group (14.98 ± 5.90) and glazing group (10.63 ± 5.39) (p < 0.05). After thermocycling test, the SBS significantly decreased for control group (8.84 ± 2.55) and glazing group (6.18 ± 2.78) while not for airborne-particle-abrasion group (41.5 ± 7.95). One-bottle universal adhesives combined with airborne-particle-abrasion showed quite high SBS of zirconia/resin, which was appropriate for bonding of zirconia restoration. 相似文献
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《Journal of Adhesion Science and Technology》2013,27(9):1197-1209
We have studied the fracture mechanism and oil absorption in an oil-accommodating adhesive. Shear and T-peel tests were carried out for test pieces prepared from two steel plates bonded with the adhesive, which is mainly composed of epoxy resin, modified NBR, and inorganic powders. When the modified NBR content was varied from 3 to 25 wt%, both the shear and the T-peel strengths increased with the modified NBR content and levelled off at around 10 wt% modified NBR content. This behavior was coincident with that in the tear test by the samples prepared from cured adhesive. Therefore, fracture in the shear and T-peel tests is attributed to the tearing of cured adhesive. The oil absorbed in the non-cured adhesive bleeds out during curing. However, this oil can be stored in the grooves of steel plates. 相似文献
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适用于低温固化的低黏度高强度环氧树脂结构胶 总被引:1,自引:1,他引:0
以碳酸丙烯酯(PC)为活性稀释剂、自制增韧型421固化剂/快固型DETA(二乙烯三胺)固化剂作为复合固化剂,制备环氧树脂(EP)结构胶。研究结果表明:当m(EP)∶m(PC)∶m(421)∶m(DETA)=100∶20∶24∶6.0时,EP结构胶的初始黏度(60 mPa.s)相对较低,其强度和韧性俱佳(拉伸强度为45 MPa、压缩强度为70 MPa和钢/钢剪切强度为12.0 MPa);该EP结构胶可低温固化(5℃或常温固化7 d后的拉伸强度基本一致),也是一款适用于冬季施工的低黏度高强度EP结构胶。 相似文献
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室温硫化硅橡胶胶粘剂的增强方法 总被引:6,自引:0,他引:6
通过硅橡胶丙烯酸(酯)改性、自制偶联剂、选择活性高分子材料、改善填料在胶粘剂中的分散性等方法,较好地提高了双组份室温硫化硅橡胶的粘接强度。 相似文献
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研究了助剂对浸渍结构胶触变性和黏度的影响。通过对15种不同配方试样的试验研究,探讨了流平剂、稀释剂和触变剂对浸渍结构胶黏度、触变性和力学性能的影响。试验结果表明,当主剂和固化剂的比例为2:1;稀释剂的用量为主剂量的15%;流平剂、触变剂的用量分别为主剂和固化剂总量的1%、0.5%;浸渍结构胶在6r/min和60r/min时的黏度分别为7500mPa·s和2100mPa·s,触变指数为3.57,拉伸强度、弯曲强度和压缩强度分别为41.10MPa、68.08MPa和67.37MPa,具有较好的施工性能和力学性能,完全符合建筑结构胶的指标。 相似文献
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四种原料生物油-酚醛树脂胶粘剂特性研究 总被引:4,自引:3,他引:1
利用生物质快速热解液化产物制备燃料或化工产品已成为国内外的研究热点。将四种生物质原料(落叶松、杨木、棉秸秆和玉米秸秆)快速热解液化产物作为苯酚替代物,由此制备出不同种类的热解生物油-PF(酚醛树脂)胶粘剂,并探讨了胶粘剂胶接强度与热解生物油组成的关系。结果表明:落叶松热解生物油-PF胶粘剂的胶接强度最大(1.277 MPa),玉米秸秆热解生物油-PF胶粘剂的胶接强度最小(1.021 MPa);胶粘剂的胶接强度主要与热解生物油中酚类物质含量有关。 相似文献
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