MUF共缩合树脂的研制

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。     

DSC法研究MUF共缩聚树脂的固化行为

借助DSC分析技术,探讨了三聚氰胺-尿素-甲醛(MUF)共缩聚树脂在不同条件下的固化行为。运用Kissinger方法进行了动力学分析,得到了其固化反应的动力学参数和活化能。结果表明,随着升温速率的增加,MUF固化反应的最高固化温度会向高温方向移动,其固化表观活化能为50.30kJ/mol,用外推法得到了其最高固化温度为97℃。而且,固化剂的加入大大降低了树脂固化表观活化能。     

环氧树脂胶粘剂工程应用研究

采用某种型号的环氧树脂(EP)胶粘剂胶接LY12-CZ铝合金试片,在110～170℃范围内加热4 h后测定胶接件的剪切强度,并对该胶接件的不同加载速率与拉伸剪切强度的关系进行了研究。结果表明:短时高温加热对该胶粘剂的剪切强度没有影响,这有利于飞机组件的整体修复;拉伸剪切强度随着加载速率的增加而增大,这又为探讨加载速率对不同胶粘剂性能的影响提供了试验依据。     

三聚氰胺添加方式对MUF胶粘剂性能的影响

以三聚氰胺作为脲醛树脂(UF)的共聚改性剂制备MUF(三聚氰胺甲醛树脂)胶粘剂。探讨了三聚氰胺的添加方式对MUF胶粘剂性能的影响,同时对其固化特性、分子结构和耐热性等进行了分析。结果表明:三聚氰胺2次投料法可有效降低MUF胶粘剂的甲醛释放量,但其胶接强度也随之下降;同时,该MUF固化体系的外推固化温度、表观活化能和反应级数均有所增加,耐热性降低;另外,2次投料体系使MUF的相对分子质量降低、相对分子质量分布变宽。     

低毒树脂改性氯丁胶粘剂的研制

以氯丁橡胶为主要基体,与经过预反应的胶液进行反应,通过设计的正交实验来分析预反应液中各因素的影响作用。选用低毒性的溶剂,制备了一种低毒树脂改性氯丁胶粘剂。剪切强度(皮革-皮革)的实验结果表明,各因素影响作用由大到小依次为:对叔丁基酚醛树脂与氧化镁的质量比、催化剂的加入量、氯丁橡胶与对叔丁基酚醛树脂的质量比、溶剂的选取、溶胶温度。于较佳的条件下所制备的低毒胶粘剂性能良好,剪切强度可达4.3MPa。     

改性脲醛树脂胶粘剂合成的研究

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]。     

The shear bond strength of repaired high-viscosity bulk-fill resin composites with different adhesive systems and resin composite types

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?+?Adper^TMSingle 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 Adper^TMSingle 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.     

环氧-聚砜结构胶粘剂耐环境性能的研究

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。     

紫胶改性酚醛树脂胶粘剂的研究

紫胶是一种具有多种用途的天然树脂,利用紫胶改性酚醛树脂胶粘剂,有利于扩大紫胶的应用范围,提高对可再生资源的综合利用。研究了对紫胶改性酚醛树脂胶粘剂的固化时间、粘接胶合板的粘接强度和甲醛释放量进行了测定。结果表明:紫胶改性酚醛胶的固化时间与普通酚醛胶接近,粘接胶合板的粘接强度达到Ⅰ类胶合板的要求,胶合板的甲醛释放量降低。因此,用紫胶改性酚醛树脂胶粘剂是可行的。     

Influence of different surface treatments on zirconia/resin shear bond strength using one-bottle universal adhesive

ABSTRACT

This 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.     

含二氮杂萘酮结构耐热胶粘剂的研究

研究了一种含二氮杂萘酮结构耐热型环氧固化剂，与低分子质量聚酰胺复合使用得到的环氧胶粘剂具有良好的耐热性，固化工艺为140℃／2h 180℃/3h,150℃有25MPa以上的拉伸剪切强度，以及极好的高温保持率，可达到100％。详细研究了表面处理方式和固化工艺对其在常温和150℃下拉伸剪切强度的影响。     

Fracture mechanism and oil absorption of an oil-accommodating adhesive

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.     

适用于低温固化的低黏度高强度环氧树脂结构胶

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。     

湿固化压敏胶的合成研究

以丙烯酸类单体为原料制备了一种具有较高剪切强度的湿固化型压敏胶。较详细地研究了湿固化方法、单体和溶剂等因素对产物性能的影响。研究结果表明，采用硅氧烷结构的湿固化方法，当湿固化单体用量为5．0％时，所得压敏胶在湿固化前具有良好的压敏性，贮存稳定期超过6个月，经湿固化后，剪切强度可达1．47MPa。     

室温硫化硅橡胶胶粘剂的增强方法

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。     

一种中温固化高强度环氧胶粘剂的研制

以E-51、E-44为主体树脂,加入奇士增韧剂研制出一种中温固化高强度环氧胶粘剂.该胶粘剂在加入占粘料质量分数30%左右的增韧剂后,选用自制固化剂SL-1,在50 ℃×1 h+80 ℃×1 h条件下固化,其拉伸剪切强度可达42.1 MPa.     

助剂对浸渍结构胶性能的影响

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。     

四种原料生物油-酚醛树脂胶粘剂特性研究

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。     

葡萄糖苯酚树脂胶粘剂的合成

以葡萄糖代替甲醛,在碱性条件下合成了葡萄糖苯酚树脂胶粘剂。用红外光谱(IR)对其结构进行了分析,并通过正交实验获得了该树脂合成的最佳反应条件:pH=11,n(葡萄糖):n(苯酚)=8:1,反应温度120℃,催化剂用量14．3%,反血时间4 h;同时对树脂的固化条件进行了系统研究。     

果糖缩二脲树脂胶粘剂的合成

以果糖代替甲醛,在酸性条件下合成了果糖缩二脲树脂胶粘剂,并通过正交实验法获得了该树脂合成的最佳反应条件:n(果糖)∶n(缩二脲)=6∶1,催化剂用量为0.4%,反应温度为100℃,反应时间为2.5 h;同时对树脂的固化条件也进行了优选,最佳固化温度为120℃,固化剂用量为8%,固化时间为2 h。