木质素磺酸钠改性硬质聚氨酯泡沫阻燃性能研究

对利用木质素磺酸钠溶剂液化产物与聚醚多元醇复配制备改性硬质聚氨酯泡沫材料的阻燃性能进行了研究。采用甲基膦酸二甲酯(DMMP)为阻燃剂,对添加量为10%~16%范围内的改性聚氨酯泡沫材料的结构与性能进行了研究。研究结果表明,DMMP与发泡体系中的其他组分相容性好,DMMP的添加使发泡速度有所下降,但对材料的微观形貌影响不大。与未添加DMMP的泡沫材料相比,添加DMMP的泡沫材料极限氧指数提高,阻燃性增强,当DMMP添加量为16%时,材料的极限氧指数最大,为25.3;材料的压缩强度与表观密度随DMMP添加量的变化而变化,当DMMP添加量为11%时,压缩强度和表观密度都达到最大值,分别为70.55kg/m~3和0.47MPa。综合比较木质素磺酸钠改性硬质聚氨酯泡沫的力学性能和阻燃性能,当DMMP添加量为13%时,综合性能表现较优,压缩强度为0.30MPa,极限氧指数为24.99。     

甲基丙烯酸缩水甘油酯(GMA)对交联硬质PVC泡沫的影响

通过在硬质交联聚氯乙烯(PVC)泡沫中加入不同比例的甲基丙烯酸缩水甘油酯(GMA)作为泡沫的交联剂,制得了不同GMA含量的硬质PVC泡沫。对泡沫的形成,交联度,微观结构,力学性能和热性能进行了研究。结果表明,在体系中引入GMA组分会提高硬质PVC泡沫的交联度,从而影响泡沫的微观结构以及力学性能,在GMA的添加量为4 g时,泡沫的压缩强度为1. 019 MPa,拉伸强度为1. 037 MPa,弯曲强度为1. 272 MPa,综合力学性能最为优异。但是GMA的引入对材料的热性能没有显著的影响。     

模胎用高密度酚醛泡沫塑料的制备研究

以热固性甲阶酚醛树脂为基体,正戊烷为物理发泡剂,30%硫酸和冰乙酸组成混合酸为催化剂,吐温-80和甲基硅油作为匀泡剂,玻璃微珠和聚乙二醇-400为改性剂,制备出了密度200 kg/m3以上综合性能较好的高密度酚醛泡沫。研究表明,通过调节物理发泡剂与混合酸催化剂用量可以有效控制泡沫密度以及发泡凝胶时间,添加4%聚乙二醇和8%的玻璃微珠,能够改善泡沫脆性和压缩强度,通过130℃、2.5 h的后处理可以将泡沫的质量稳定。制备出的高密度酚醛泡沫塑料在180℃高温下具有高的压缩强度,尺寸变化率在1%以内,有望作为新型模胎材料使用。     

一步法制备热塑性聚酰亚胺泡沫关键因素探讨

通过在热塑性聚酰亚胺(PI)粉末中添加高温发泡剂一步发泡制得PI泡沫材料,探讨了一步法制备PI泡沫过程中的模具密闭性、发泡温度、发泡剂用量等几个关键因素对材料结构及力学性能的影响。结果表明,一步发泡法制备PI泡沫材料过程中模具密闭性、发泡剂用量对泡沫性能有很大影响。经优化的制备条件为:树脂粉在烘箱中60℃预处理2 h,发泡剂质量分数为2%,成型温度为280℃,成型压力为10 MPa,发泡时间为30 min。在优化的实验条件下制备的热塑性PI泡沫材料样品的密度为0.463 g/cm3时,压缩强度为10.86 MPa,冲击强度为6.2 kJ/m2,弯曲强度为12.8 MPa。     

短切碳纤维增强聚酰亚胺泡沫的制备及性能

针对现有软质聚酰亚胺泡沫强度低的缺点,通过一步法制备了短切碳纤维增强聚酰亚胺泡沫,研究了短切碳纤维的添加量对聚酰亚胺泡沫的化学结构、微观形貌、压缩强度及热导率的影响。结果表明,短切碳纤维在发泡过程中起到成核剂的作用,随着其添加量的增加,泡沫的泡孔平均尺寸先减小后增加;当短切碳纤维质量分数为20%时,泡孔的最小平均尺寸为507μm;泡沫密度随着短切碳纤维用量的变化没有明显的改变;泡沫的压缩强度随着短切碳纤维的用量先增大后逐渐减小,压缩强度最大为54.52 kPa;短切碳纤维的加入对聚酰亚胺泡沫材料的化学结构和热稳定性没有明显的影响,但是材料的热导率随着短切碳纤维含量的增加有一定的增加。     

PMI泡沫材料的制备及性能研究

采用偶氮二异庚腈(ABVN)为引发剂,尿素/甲酰胺为复合发泡剂制备了一种高性能聚甲基丙烯酰亚胺(PMI)泡沫材料。重点考察了不同配比的混合发泡剂用量对PMI泡沫材料性能的影响。结果表明:通过改变两种发泡剂的用量可以获得泡孔均匀且密度为38.39⁷5.99 kg/m3的PMI泡沫材料,而PMI泡沫的力学性能和热性能与泡沫密度呈正相关。当尿素和甲酰胺的用量都为1 phr时,所得PMI泡沫材料具有最佳综合性能,其拉伸强度和压缩强度分别为2.0 MPa和1.42 MPa,玻璃化转变温度(Tg)为217.7℃。     

环氧树脂复合泡沫材料的制备及压缩性能研究

以空心玻璃微珠填充环氧树脂制备高强复合泡沫材料,在选取不同种类室温固化剂的基础上,研究了空心玻璃微珠含量对复合泡沫材料压缩性能的影响。研究表明当空心玻璃微珠质量分数为105%时,复合泡沫材料的比强度达最大值,此时压缩强度为62.91MPa,密度为0.55g/cm3。     

水性环氧树脂制备及其砂基透水材料应用

由聚乙二醇1000和环氧氯丙烷反应制得聚乙二醇二缩水甘油醚(PEGDGE1000)。PEGDGE1000再与双酚A(BPA)反应得到二缩水甘油醚聚合物(BPA PEGDGE1000)。将以上2种亲水性环氧树脂添加在专用环氧胶粘剂RCZM中,并以此制备了砂基透水材料。通过对胶粘剂固化物接触角及透水材料的压缩强度和透水速率测试研究了2种环氧树脂对透水材料性能的影响。结果发现,添加PEGDGE1000和BPAPEGDGE1000后,胶粘剂与水的接触角更小,亲水性进一步增强。加入BPA PEGDGE1000的透水材料的透水速率增加,在一定范围内压缩强度亦增加,解决了砂基透水材料的压缩强度与透水速率互相制约的问题。由BPA PEGDGE1000添加质量分数10%的RCZM制备的砂基透水材料的透水速率≥3.0 mL/(min·cm2),是行业标准的1倍以上,且压缩强度≥30 MPa。     

分子结构对聚酰亚胺泡沫熔体粘度和形貌的影响

研究了含2,3,3',4'-联苯四酸二酐(a-BPDA)的聚酰亚胺(PI)泡沫材料体系中,泡沫前驱体树脂的热处理温度、计算分子量、二酐分子结构对聚酰亚胺前驱体树脂熔体粘度和泡沫形貌的影响。研究发现,对于a-BPDA/m-PDA/NA体系,计算分子量为1500、密度为100 kg/m3时,前驱体树脂经过260℃/1 h的热处理得到的泡沫材料泡孔均匀、闭孔率可达89%,压缩强度为1.34 MPa,压缩模量为37.1 MPa;在该体系中,部分引入ODPA或BTDA,可降低材料制备成本,同时拥有PI泡沫原有的形貌和闭孔率。     

环氧树脂复合泡沫材料的制备研究

以缩水甘油酯环氧树脂(EP)、酸酐固化剂和空心玻璃微珠为主要原料,通过添加一定的活性稀释剂,高温固化制备了EP复合泡沫材料。研究了空心玻璃微珠的表面改性对复合泡沫材料性能的影响。结果表明,复合泡沫材料性能与空心玻璃微珠的表面性能密切相关,当EP/固化剂/稀释剂的质量比为100/120/15、KH-560改性的空心玻璃微珠用量为30份时,所制备的复合泡沫材料密度为0.826 g/cm3,压缩强度达115.8 MPa,比强度为140.2。     

Preparation and properties of nano ZnO toughed phenol–urea-formaldehyde foam

Urea formaldehyde (UF) and phenol formaldehyde (PF) foam possess outstanding flame-retardant properties, excellent insulation, and low thermal conductivity. These properties make them suitable for thermal insulation in buildings. However, the mechanical properties still need to be improved. In this study, orthogonal test was designed to optimize the level components of PF/UF composite foam first, then nano ZnO was added to the PF/UF composite foam to improve its toughness. The effects of nano ZnO on the morphology, apparent density, pulverization rate, thermal conductivity and thermal degradation property, flame retardancy, and mechanical properties of the ZnO/PF/UF nanocomposite foam were studied. The addition of nano ZnO improved the bending and compressive strength and decreased the pulverization rate of the composite foam significantly. The ZnO/PF/UF nanocomposite foam also presented better flame retardant properties than PF/UF composite foam. The largest oxygen index values of ZnO/PF/UF nanocomposite foam could reach 39.31%, while the thermal conductivity and the maximum rate of weight loss temperature were increased to 0.036 W/(m∙K) and 279°C, respectively. Moreover, ZnO/PF/UF nanocomposite foam showed low apparent density property (0.27 g/cm³).     

改性脲醛树脂泡沫塑料的制备

采用加入木质素磺酸钠改性脲醛树脂,以降低游离甲醛含量及充分利用木质素资源;同时加入三聚氰胺和聚乙烯醇,以改变树脂的柔韧性。通过碳酸氢铵发泡法发泡制得开孔改性脲醛树脂泡沫塑料。实验结果表明:改性后游离甲醛含量明显降低,韧性有了较大的提高。     

ABS微孔发泡材料气体扩散行为分析

采用化学交联模压法制备了丙烯腈-苯乙烯-丁二烯共聚物(ABS)微孔发泡材料,研究了发泡温度、发泡压力及发泡时间对ABS微孔发泡材料气体的扩散行为及泡孔结构的影响,结果表明:气体吸收量随着发泡温度、发泡压力和发泡时间的增加,先增大后减小;随着气体吸收量的增加,制品的泡孔尺寸逐渐减小,泡孔密度逐渐增大,增加气体吸收量有利于提高发泡效果。当发泡温度为170℃、发泡压力为10 MPa、发泡时间为12min时,泡孔密度约为2.87×108个/cm3,可满足工业上微孔发泡材料泡孔密度的要求。     

竹碎料板用低毒脲醛树脂的合成工艺研究

在脲醛树脂(UF)的制备过程中,采用三聚氰胺对UF进行改性,制得低毒UF。结果表明:该低毒UF的固含量为49.88%,游离甲醛释放量仅为0.2026%;采用这种低毒UF胶粘剂压制的竹碎料板,其静曲强度为22.6MPa,弹性模量为2056MPa,内结合强度为0.58MPa,2h吸水厚度膨胀率为2.57%;该低毒UF是一种综合性能良好的木材用胶粘剂,其应用前景非常广阔。     

Hydrolyzed soy protein isolates modified urea–formaldehyde resins as adhesives and its biodegradability

The hydrolytes soy protein isolates (HSPI)-modified urea–formaldehyde (UF) resins were synthesized via copolymerization process. The best bonding strength is 1.50 MPa and improves 51.5% compared with pure UF. In addition, the formaldehyde emission decreased. The effect of (HSPI) on the biodegradable (UF) resins was investigated. Biodegradation was evaluated by composting under controlled conditions in accordance with ISO 14855. The faster degradation rate was obtained when lower hydrolysis degree of HSPI was added into the system. Characterization of the resulting samples was performed by attenuated total reflection Fourier transform infrared spectroscopy, thermo-gravimetric analysis, XRD, scanning electron microscopy, and AFM. The results showed that no evidence of biodegradation was found for UF resins. The UF modified with lower hydrolysis degree of hydrolytes soy protein isolates (HSPI) resulted in a faster degradation rate. The HSPI in the network of modified UF degraded first, which resulted in the broken of the network of HSPI-modified UF resins. The thermal stability of degraded resins was found to be enhanced as the mineralization time increased. Not only the surface of the sample was degraded, but also the crystalline regions of the samples were also decomposed. The degradation on the modified UF surface occurs mainly via the formation of holes. The roughness of the degraded surfaces of modified UF resins increases with the hydrolysis degree of HSPI decreases. The presence of HSPI has driven the degradation of urea–formaldehyde. The modified resins used as adhesives in biodegradable seedling container can be seen as a controlled release source of nitrogen fertilizer.     

聚乳酸/淀粉发泡片材的制备及性能

以甘油为增塑剂,偶氮二甲酰胺为发泡剂(AC发泡剂),采用模压法制备聚乳酸/淀粉发泡片材。通过对材料的力学性能,发泡密度、发泡倍率等测试研究了发泡剂含量、发泡温度、发泡时间及发泡压力对片材性能的影响。结果表明,发泡温度、发泡时间及发泡压力对片材的力学性能影响较大,AC发泡剂对材料发泡性能影响显著。当AC发泡剂用量为0.6份,发泡温度为200℃,发泡时间为4 min,压力为10 MPa时片材的拉伸强度达到27.91 MPa,断裂伸长率为3.65%,此时材料的发泡密度为1.08 g/cm3,发泡倍率为1.16,综合性能最佳。     

Fabrication of foamed polypropylene with excellent behaviors by adding a special foam stabilizer

Foamed polypropylene (PP) has attracted more and more attention in recent years due to its unique properties, such as heat resistance and high flexural modulus. In this work, foamed PP with excellent properties was successfully fabricated by adding a special foam stabilizer, which was prepared by a simple one-step strategy using fatty acid and amino silicone oil as reactants. The two-component stabilizer mixed uniformly with PP and reduced the surface tension during foaming. The foam stabilizer significantly reduced density and cell diameter of the foam. When the amount of foam stabilizer was 1.0 wt%, the density dropped to 0.958 g/cm³, about 2.8% lower vs foam generated without stabilizer. The tensile strength increased to 18.4 MPa from 16.1 MPa, and the elongation at break increased to 495% from 328%.     

Effects of hydrolysis degree of soy protein isolate on the structure and performance of hydrolyzed soy protein isolate/urea/formaldehyde copolymer resin

The hydrolyzed soy protein isolate (HSPI) with different hydrolysis degree was applied to modify urea‐formaldehyde resins (UF) via copolymerization process. The properties of HSPI were characterized by attenuated total reflection Fourier transform infrared spectroscopy (ATR‐FTIR) and TGA. The results show that HSPI with different hydrolysis degree is obtained. ¹H NMR and ATR‐FTIR spectra indicate that HSPI with different hydrolysis degree can incorporate into the structure of cured and uncured UF. The UF modified with higher hydrolysis degree of HSPI possess more stable units and contribute to the lower exothermic peak temperature in DSC curves. The bonding strength of HSPI modified UF increases as the hydrolysis degree of HSPI increases at the hot‐press temperature of 120°C and decreases at the hot‐press temperature of 150°C. The best bonding strength is 1.53 MPa at the hot‐press temperature of 135°C and improved 56.12% compared with UF. In addition, the formaldehyde emission is dramatically reduced. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41469.     

In situ preparation of intrinsic flame-retardant urea formaldehyde/carbon nanotubes nanocomposite foam: structure and reinforcing mechanism

ABSTRACT

Urea-formaldehyde (UF)/carboxylated carbon nanotubes (CNTs-COOH) nanocomposite foams were prepared via in-situ polymerization. Chemical bonding and hydrogen bonding interactions formed between CNTs-COOH and UF matrix. UF resin adhered onto the ektexine of CNTs-COOH and grafting ratio of 496.41% was achieved. UF/CNTs-COOH foam showed smaller cell size, narrower cell size distribution and lower water absorption compared with UF foam. Introduction of 0.25 wt% CNTs-COOH resulted in 58.43% increase in compressive strength. CNTs-COOH were pulled out with surface covered with UF resin under stress and the failure mode was the destruction of matrix around interfacial layer. UL-94V-0 rating was achieved for the composite foams.     

落叶松生物油改性脲醛树脂胶粘剂的制备与性能研究

以自制落叶松热解生物油为原料,采用萃取法制备富酚油;然后以此作为UF(脲醛树脂)的改性剂,考察了富酚油含量对改性UF胶粘剂性能的影响。结果表明:富酚油组分复杂,其中酚类物质含量为53.87%;当w(富酚油)=10%(相对于尿素质量而言)时,改性UF胶粘剂的综合性能较好,由其压制而成的3层杨木胶合板的胶接强度(1.23 MPa)和甲醛释放量(1.05 mg/L)均优于未改性UF胶粘剂。