热稳定性

Abstract(#br)Self-healing anticorrosive coatings require healing agents with hydrophobic properties and low glass transition temperature. Polydimethylsiloxanes are group of compounds with high degree of hydrophobicity and very low glass transition temperatures. The nature of functional group of core material highly affect the properties of resultant microcapsules.

Abstract\n\t\t\t\t\n\t\t\t\t\tA novel cross-linker octa[(trimethoxysilyl)ethyl]-POSS (OPS) based on a Vinyl-POSS derivative was firstly prepared via hydrosilylation chemistry. The novel POSS cross-linker was applied to hydroxyl terminated polydimethylsiloxane (HPDMS) matrix to prepare a series of novel RTV silicone rubbers. The chemical incorporation of novel POSS cross-linker into PDMS by hydrolytic condensation reaction was verified by attenuated total reflection (ATR) infrared spectroscopy.

Polystyrene-graft-polydimethylsiloxane (PS-g-PDMS) copolymers with different PDMS content were syn-thesized by the radical bulk copolymerization of PDMS macromonomer and styrene. The copolymers were charac-terized by Fourier transform infrared (FT-IR),1H-nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), transmission electron microscopy (TEM) and the mechanical properties of the copolymers were also carried out.

To improve the heat resistance of acrylic-based pressure-sensitive adhesive (PSA), silicone-block-containing acrylic PSAs (SPSAs) were synthesized using a polydimethylsiloxane (PDMS)-based macro-azo-initiator (MAI). To evaluate the heat resistance of the PSA films, the probe tack and 90° peel strength were measured at different temperatures. The acrylic PSA showed that its tack curves changed from balanced debonding at 25 °C to cohesive debonding at 50 °C and exhibited a sharp decrease.

为了提高丙烯酸基压敏胶( PSA )的耐热性，采用聚二甲基硅氧烷( PDMS )基宏观偶氮引发剂( MAI )合成了含硅嵌段的丙烯酸PSAs ( SPSAs )。为了评价PSA薄膜的耐热性，在不同温度下测定了探针钉和90°剥离强度。丙烯酸PSA表明，其黏着曲线由25℃的平衡脱粘转变为50℃的黏聚脱粘，并呈现急剧降低的趋势。但在SPSA含20wt % MAI ( MAI20 )的情况下，平衡脱粘保持在75℃，其粘着值几乎不随温度变化。随着MAI含量的增加，SPSA中PDMS-与丙烯嵌段之间的微相分离导致25℃下的剥离强度降低，但剪切粘着破坏温度( SAFT )从41.3℃几乎线性增加到122.8℃。由于加入20wt %的有机硅-聚氨酯二甲基丙烯酸酯齐聚物和200 m J / cm2的紫外光照射剂量，MAI20在25℃时的90°剥离强度显著提高(原MAI20为548.3 vs . 322.4 gf / 25 mm )。通过剪切粘着破坏试验( SAFT )评估其在剪切应力作用下的耐热性，与未辐照试样相比，其破坏温度提高到177.3℃。