###### Abstract  
It is a challenge to research and develop silicon surfactants with good acid and alkali stability. In the present paper, methylpropenyl polyether modified nonionic silicone surfactant (MPNTS), an alkali-resistant and hydrolysis-resistant silicone surfactant, was synthesized by hydrosilylation of 1,1,3,5,5,5-heptamethyl trisiloxane (MD\({}^{\text{H}}\)M) and methylpropenyl polyether (EO(7)). The polyether segments are grafted onto the main chain of organosion heptamethyl trisiloxane at a molar ratio of 1:1.05 (n(Si-H)=n(C=C)). To evidence product formation, the MPNTS were analyzed by FT-IR and \({}^{1}\)H NMR spectroscopy. The surface tension of NPNTS is 18.68 mN/m, and the CMC value is 78 mg/L by a contact angle tester. MPNTS shows hydrolytic stability and maintains that it could keep surface activity after standing for 60 days at pH = 7-10. The compatibility performance analysis shows that MPNTS has good compatibility and synergy with cationic, anionic, and nonionic surfactants, and it reveals the application prospects in daily chemicals, agricultural adjuvants, and other products.  
silicone surfactant; trisiloxane; stability; synergy +
Footnote †: journal: Applied Sciences  
also maintain product activity and good acid and alkali resistance and have better stability than hydrocarbon siloxane [16].  
Polyether trisiloxane is a kind of modified silicone surfactant formed by introducing polyether segment modification with excellent extensibility, so that the hydrophobic surface can be well infiltrated, and the hydrophilic surface can be completely spread [17]. It has a good synergistic effect on some hydrophobic products [18], especially coatings [19], cosmetics [20], toiletries [21], etc. However, the application of polyether trisiloxane still faces many challenges. This is due to the fact that, in the silicone skeleton, Si-O-Si and C-O-C are sensitive to hydrolysis [22], and the polarity of the silicon-oxygen bond is strong [23], which easily reacts with acid, alkali, aqueous solution, and alcohol, resulting in hydrolysis. In fact, there are many causes for the hydrolysis of silicone surfactants. More specifically, previous studies have proved that pH and time are the main factors causing hydrolysis. [PERSON] et al. [24] studied the hydrolytic stability of SilwetL-77. When SilwetL-77 was in weakly acidic or weakly alkaline solutions, it could be stably stored for 60 days. However, it was hydrolyzed quickly in a strong acidic or alkaline solution. The hydrolysis of trisiloxane in acid or alkaline is caused by molecular rearrangement. Therefore, it is very necessary to find ways to improve their hydrolytic stability.  
In this paper, methylpropenyl polyether was introduced to change the group grafted on the main chain of trisiloxane to maximize its hydrophilicity [25], and on this basis, to changing the change in extensibility caused by the long chain segment. There are few studies on its hydrolytic stability, and this present paper focuses on the stability and application performances. We have successfully synthesized an alkali-resistant hydrolyzed methyl allyl polyether trisiloxane (MPNTS) with a simple process, and we systematically tested its surface tension, hydrolysis stability, and compatibility. In order to explore its stability and application, this paper provided a new scheme for the application of silicone surfactants in daily chemical products.