新型环保海洋防污材料研究进展

简要论述了海洋防污材料的发展历史及其防污机理,评述了新型环保高性能海洋防污材料的最新研究进展。自有机锡自抛光防污涂料被禁用后,基于聚丙烯酸锌、聚丙烯酸铜和聚丙烯酸硅烷酯的无锡自抛光防污涂料得到了广泛应用。为进一步提升其防污性能和环保性能,接枝防污官能团防污材料、生物降解高分子基防污材料、主链降解型自抛光防污材料、减阻型防污材料以及仿生防污材料成为当今的研究热点。介绍了席夫碱、草甘膦、苯并异噻唑啉酮等几种防污官能团的接枝方法及其防污效果,指出这类方法可提高防污剂的利用率,使防污剂释放更平稳,但实用化还需解决防污剂接枝改性后防污能力下降以及合成工艺复杂等问题。重点介绍了生物降解高分子基防污材料,特别是主链降解-侧链水解型防污材料的结构和合成方法。由于该类可降解/水解树脂具有良好的力学性能和水解可调控性,所制备的防污涂料即使在静态下,防污剂也释放平稳,因此可用于开发新型主链降解型自抛光防污涂料,以提高涂层的静态防污长效性,具有良好的应用前景。还介绍了通过对高分子树脂改性等方法降低涂层水解后的表面粗糙度,该类防污涂层具有良好的减阻性能。最后介绍了仿生防污材料的研究进展。     

Experimental and numerical investigation on the ablation mechanism of Al2O3/Al2O3-CMCs under continuous-wave laser irradiation

In this study, the ablation mechanism of Al₂O₃/Al₂O₃-CMCs under laser irradiation and the influence of laser parameters on the ablation efficiency were examined. The experimental results show that the diameters of the ablation centre and transition area are both positively correlated to the irradiation energy, and the irradiation power has a more prominent effect on the diameter of the ablation centre. The molten Al₂O₃ changes the reflection and transmission properties of laser beam, which results in an elliptical ablation pit. A macro-meso two-scale finite element (FE) model was established to simulate the laser ablation process progressively. The FE results show that the difference in thermal conductivity between the Al₂O₃ fibre and matrix induces a discrepancy in ablation at the mesoscale. The radius and depth of the ablation pit increase rapidly at the initial stage, then slowly increase with time. A good correlation between the experimental and numerical results was achieved.     

Degradable polyurethane based on star-shaped polyester polyols (trimethylolpropane and ɛ-caprolactone) for marine antifouling

The star-shaped polyester polyols based on initiators (trimethylolpropane or pentaerythritol) and ɛ-caprolactone were prepared by polycondensation reaction. The degradable polyurethane (PU) films were prepared by mixing star-shaped polyester polyols and crosslinker agent (hexamethylene diisocyanate trimer). The hydrolytic degradation and water absorption experiments demonstrated that the PU films could erode in artificial sea water, which were controlled by varying the ratios of ɛ-caprolactone/trimethylolpropane and the arm number of star-shaped polyester polyols. The mechanical properties of PU films and coatings increased with decreasing the ratios of ɛ-caprolactone/trimethylolpropane and increasing the arm number of star-shaped polyester polyols. The surfaces of PU films and coatings kept eroding, which were revealed by scanning electron microscopy. The copper ion release rates from PU coatings reached steady state at about 31 days. The marine field tests of PU coatings demonstrated that the degradable PU coatings based on star-shaped polyester polyols were effective coatings for marine antifouling.     

己内酯/乙交酯嵌段共聚物的合成及水解行为研究

以辛酸亚锡为催化剂,合成了己内酯预聚物(PCL),再与乙交酯(GA)熔融共聚,制备了嵌段型己内酯乙交酯共聚物(PCL/GA)。利用GPC、FT-IR、1H-NMR和13C-NMR等对PCL/GA的结构进行了表征,确认合成的共聚物为嵌段型聚酯共聚物。利用XRD和DSC测试了PCL/GA的结晶状态和热学性能,测试发现合成的共聚物均为结晶型聚合物,且结晶情况与单体组成有关,利用石英微晶天平考察了PCL/GA(80/20)在海水中的水解行为,发现前3 h聚酯降解速率波动较大,推断是由于初期嵌段聚酯吸水与降解作用同时进行所致,随着吸水作用的完成,后期嵌段聚酯的降解速率维持在80 ng/(cm2.h)左右,降解速率稳定。利用POM、SEM观察了水解过程中薄膜结晶及形貌变化。     

核壳型Fe3O4-聚吡咯电磁屏蔽填料的制备与表征

采用一步刻蚀法制备了核壳Fe₃O₄-聚吡咯(Fe₃O₄-PPy)复合微球,并采用FT-IR、XRD、TG和矢量网络分析仪对其结构和电磁参数进行了表征。结果表明:盐酸刻蚀产生的Fe ³⁺引发了吡咯在Fe₃O₄微球表面的聚合。扫描电镜与透射电镜证实了其核壳结构;FT-IR谱图证明了聚吡咯的生成;XRD谱图证明了在反应过程中核的晶型没有变化。热重曲线与磁滞回线表明:随着反应时间的延长,Fe₃O₄的含量减少而聚吡咯的含量增加。当反应时间为5 min时,该样品的吸波性能最优,最低反射损耗为-41.9 dB,有效吸收带宽达到6 GHz。Fe₃O₄-PPy基电磁屏蔽涂层在30 MHz~1 GHz的电磁屏蔽效能≥36 dB。     

Corrosion protection of waterborne epoxy coatings containing mussel-inspired adhesive polymers based on polyaspartamide derivatives on carbon steel

A novel mussel-inspired adhesive polymer (PHEA-DOPA) containing the 3,4-dihydroxyphenylalanine (DOPA) functional group based on polyaspartamide derivatives was synthesized. The corrosion protection of the waterborne epoxy coatings containing the adhesive polymers was investigated by electrochemical impedance spectroscopy (EIS). The results indicated that the PHEA-DOPA could improve the corrosion resistance of the waterborne epoxy coating. The corrosion products were also analyzed by Raman microspectroscopy (RM), indicating the formation of the insoluble DOPA-Fe complexes on the carbon steel surface. These complexes simultaneously acting as a passivating layer, can inhibit the process of corrosion at the metal-solution interface. The differential scanning calorimeter (DSC) measurement indicated that PHEA-DOPA can increase the crosslinking density of coating. The effect of O₂ on the protective mechanism of the PHEA-DOPA coating in a 3.5% NaCl solution was also evaluated by EIS. The results indicated that the barrier effect was significantly improved under aerated conditions because DOPA was oxidized to DOPA–quinone (Dq) by O₂, which triggered the reaction with Fe ions that were released from the surface of the carbon steel. This led to more compact coatings.     

一种反射型有机/无机复合高能激光防护涂层制备及性能研究

以酚醛树脂、环氧树脂为粘结剂，采用单一因素考察法，分别考察了ZrO₂和Al₂O₃共2种具有高反射率的耐热填料对高能激光防护涂层性能的影响，分别对其抗高能激光烧蚀性能、耐激光辐照时间、激光辐照前后涂层表面反射率等性能进行了表征，开展了辐照前后涂层表观形貌观察及XRD扫描，从微观角度确定了耐热填料晶型变化情况。结果表明，ZrO₂在高能激光辐照过程中具有良好的耐高能激光烧蚀性能，可耐受高能激光辐照功率密度达到2.35 kW/cm2，激光辐照前后涂层表面反射率提高了46.28%。      

Polyaniline synthesis: influence of powder morphology on conductivity of solution cast blends with polystyrene

Synthesis of polyaniline (PANI) was performed under different conditions followed by dedoping, redoping with dodecyl benzene sulfonic acid (DBSA) and then blending with PS. The morphologies of the as-polymerized, doped and blended PANI were studied. The main polymerization stages seem to include: PANI oligomers assembling into nuclei, nuclei growing into primary particles (10 nm), primary particles assembling into aggregates (≈0.5 μm) and aggregates assembling into agglomerates (≈10 μm). The morphology of the as-polymerized PANI was found to be strongly related to the rate of oxidant addition, synthesis duration and synthesis temperature. This morphology dominates the effects of DBSA doping and dispersing the resulting PANI–DBSA in the matrix polymer. A fine PANI–DBSA powder with weakly bound aggregates is likely to disperse well in a solvent and hence promote the formation of the desired fine-network morphology and yield a low percolation threshold and high conductivity. Synthesis at a high oxidant addition rate, an excess of oxidant, a relatively high polymerization temperature and a short synthesis duration should diminish the tendency to form dense complex structures. These dense structures prevent efficient DBSA doping, deaggregation and the desired fine-network dispersion of PANI–DBSA in the blends.