A double-layer aluminum consisting of an aluminum core and a shellof SiO_2 and polyacrylic acid was synthesized.This modified aluminum was used to improve the corrosion resistance and dispersive property of aluminum in waterborne media.TEM,FTIR,XPS,and EDX determination showed that PAA and SiO_2 were coated on the surface of aluminum.Evolved hydrogen detection showed that the corrosion resistance of composite particle had been markedly improved.Maximum corrosion inhibition efficiency of SiO_2 coated aluminum(SiO_2@Al)was 95.1% while that of double-layer coated aluminum(PAA/SiO_2@Al)was 98.8%.Meanwhile,polyacrylic acid layer improved the agglomeration of aluminum significantly.According to the dispersibility test,the particle size of 50% volume fraction [d(0.5)] of aluminum,SiO_2@Aland PAA/SiO_2@Alwere 42,53,and 34 μm,respectively.
Amino silicone resins were synthesized through a three-step method using(3-aminopropyl) triethoxysilane(APTES), methyltrimethoxysilane(MTMS) and end-capping agents, The products were characterized by Fourier transformed infrared spectroscopy(FT-IR), nuclear magnetic resonance(1H NMR), element analysis and gel permeation chromatography(GPC). The results of 1H NMR indicate that the chemical shift signal of acid-catalyzed products is weak at δ3.4(attributing to alkoxy). FT-IR shows that there is a vibration peak of Si—OH at 3 100-3 600 cm-1 and the intensity of the peaks is most weak at 6h. The results show that this method cannot only effectively reduce the residue of alkoxy groups and Si—OH groups, but also obtain the products with sufficient amino group. It concludes that this resin is suitable as modifier in the silicone rubber.
To develop an efficient and bio-compatible way to improve the thermal and mechanical properties of addition type liquid silicone rubber(LSR), a series of modified LSR samples were prepared by introducing octavinyl-polyhedral oligosilsesquioxanes(VPOSS) and high purity silicon sol singly or in combination before vulcanization. Significant correlation was found between the loading rate of VPOSS and thermal properties. However, mechanical properties were negatively correlated with VPOSS content within the range experimented, which may be ascribed to material defect caused by uneven distribution and aggregation. Furthermore, test results approved that the introducing of silicon sol indeed affected the stabilities of the polymer by restraining the material defect caused by the aggregation of POSS molecules and improving cross link density. For example, adding 10%-20% of silicon sol into VPOSS(1.0%) modified LSR will increase tear resistance by 43.9%-85.7%, elongation at break by 31.7%-57.3%, residue at 800 ℃ in N2 atmosphere by 32.0%-37.9%, residue at 650 ℃ in air atmosphere by 70.9%-91.6%, respectively. This work proves that, to incorporate VPOSS into LSR by hydrosilylation, and to use silicon sol as dispersant and reinforce filler can become an efficient way to improve the mechanical property, thermal stability and bio-compatibility of LSR in the future.
制备了以碳球(CS)为核、甲基丙烯酰氧乙基三甲基氯化铵(DMC)为壳的阳离子球形聚电解质刷(CS-PDMC),探讨了其与阴离子聚丙烯酰胺(APAM)形成的二元体系中CS-PDMC用量对两种填料(重质碳酸钙(GCC)、高岭土)的首程留着率及浆料滤水性能的影响。当浆料中GCC用量15%时,加入用量0.8%的CS-PDMC(相对于绝干浆,以下同),GCC的首程留着率最高,为79.3%;当浆料中高岭土用量15%时,加入用量1.0%的CS-PDMC,高岭土的首程留着率最高,为88.5%。当浆料中GCC用量10%时,加入用量0.8%的CS-PDMC,浆料滤水速度最快,为0.91 m L/s;当浆料中高岭土用量5%时,加入用量0.8%的CS-PDMC,浆料的滤水速度最快,为0.83 m L/s。
