Objectives

To evaluate the stability and reactivity of γ-methacryloxypropyl trimethoxysilane (MPTMS) in commercially available primers and adhesives.

Methods

Four representative primer formulations [Calibra Silane Coupling Agent/Dentsply (CLB), G-Multi Primer/GC (GMP), Kerr Silane Primer/Kerr (KSP), Monobond Plus/Ivoclar Vivadent (MBP)] and a universal adhesive [Scotchbond Universal/3M ESPE (SBU)] containing MPTMS were analyzed spectroscopically. For the stability study, the silanol content was evaluated in bulk solutions as received (reference-RE) and after aging (AG, 48 °C/1 month) by ¹H, ¹³C, ³¹P NMR and in fresh films by transmission FTIR analysis (TIR, films applied on Ge windows after solvent evaporation). The reactivity, as expressed by the siloxane formation capacity of the RE products, was evaluated by micro-multiple internal reflectance FTIR analysis (MIR, films applied on Ge crystals) after drying and ethanol rinsing (t₀) and following 1 (t₁) and 24 h (t₂₄) storage (air/37 °C).

Results

NMR and TIR showed ∼60% MPTMS silanol groups in RE-CLB, with the other (∼40%) groups being methylated or ethoxylated. In AG-CLB, the silanol peaks further decreased, while ethoxylation and siloxane derivatization increased. In all other products and aging conditions no silanols were traced and formation of small- and large-size MPTMS derivatives was evident. Apart from the 10-MDP molecule, phosphorous impurities were identified in all RE specimens (2–5%), which after AG reached a maximum value of 15% (MBP). MIR analysis showed siloxane formation in all products, regardless the presence of free silanols (t₁), which further increased at t₂₄ especially in CLB, GMP and MBP.

Significance

MPTMS silanols are very sensitive to mild thermal aging. Incorporation of MPTMS in the same vials with adhesive and conventional methacrylate monomers, results in derivatization with no detectable silanols, even in fresh materials. The condensates formed may induce additional siloxane formation due to residual activity, which greatly varies among the materials tested. These may have a detrimental effect on MPTMS silanol chemisorption and bonding capacity.

中文翻译：

---

γ-ΜPTMS硅烷在某些商业底漆和粘合剂配方中的稳定性和反应性

目标

为了评估γ-甲基丙烯酰氧基丙基三甲氧基硅烷（MPTMS）在市售底漆和粘合剂中的稳定性和反应性。

方法

四种代表性的底漆配方[Calibra硅烷偶联剂/登士普（CLB），G-Multi底漆/ GC（GMP），Kerr硅烷底漆/ Kerr（KSP），Monobond Plus / Ivoclar Vivadent（MBP）]和通用粘合剂[Scotchbond Universal对包含MPTMS的/ 3M ESPE（SBU）]进行了光谱分析。为了进行稳定性研究，评估了原液（参比-RE）和老化（AG，48°C / 1个月）于¹ H，¹³ C，³¹老化后的硅烷醇含量通过透射FTIR分析（TIR，溶剂蒸发后在Ge窗口上施加的膜）进行P NMR和新鲜膜分析。在干燥和乙醇冲洗后（t ₀）及随后的1（t ₁），通过微多重内反射FTIR分析（MIR，Ge膜上的涂膜），对RE产品的硅氧烷形成能力表示的反应性进行了评估。和24小时（t ₂₄）储存（空气/ 37°C）。

结果

NMR和TIR显示RE-CLB中约60％的MPTMS硅烷醇基团，其他（约40％）基团被甲基化或乙氧基化。在AG-CLB中，硅烷醇峰进一步降低，而乙氧基化和硅氧烷衍生化增加。在所有其他产品和老化条件下，均未发现硅烷醇，并且明显形成了大小尺寸的MPTMS衍生物。除10-MDP分子外，在所有RE标本中都鉴定出了磷杂质（2％至5％），AG达到15％（MBP）后，磷杂质含量最高。MIR分析表明，无论是否存在游离硅烷醇（t ₁），所有产品中均会形成硅氧烷，这在t _24时会进一步增加，尤其是在CLB，GMP和MBP中。

意义

MPTMS硅烷醇对温和的热老化非常敏感。在同一小瓶中将MPTMS与粘合剂和常规的甲基丙烯酸酯单体合并，即使在新鲜的材料中，也导致衍生化，没有可检测到的硅烷醇。形成的冷凝物可能会由于残留活性而导致额外的硅氧烷形成，而残留活性在所测试的材料之间差异很大。这些可能会对MPTMS硅烷醇的化学吸附和键合能力产生不利影响。