Synthesis And Application Of Hydroxyproplv Terminated Polysiloxanes

Hydroxyalkyl-containing polysiloxanes were a sort of functional silicone which had active hydroxyalkyl groups.They had special and excellent performances in many aspects.Hydroxyalkyl-containing polysiloxanes and their derivatives were widely used in many fields such as medical treatments,electrical uses,personal care,coatings,and the modification of organic polymers.The synthetic technology and structure adjustment of hydroxyethoxypropyl terminated silicone oil were studied.Their application in anti-graffiti coating was systematically researched,and the pilot-scale experiment was carried out.The specific work was as follow:1.Preparation and Structure modification of hydroxypropyl terminated silicone oil?PDMS-OH?.Using tetramethyldisiloxane?MMH?as a termination agent,hydrogen silicone oil?PDMS?with various molecular weights was prepared by ring opening polymerization of dimethyl siloxane cyclic mixture?DMC?with acid as a catalyst.Then PDMS-OH was prepared by hydrosilylation reaction of PDMS and 2-allyloxyethanol.The effects of catalyst concentration?Cat%?,initial reaction temperature?RT₀?,reaction temperature?RT₁?,reaction time?t?and so on were studied,The optimized condition was obtained:Cat%=7 ppm,RT₀=60?.RT₁=80?,t=4 hr,the PDMS-OH with viscosity 56.7 mm2/s,molecular weight 2880,refractive index 1.4115 was obtained.Also the effect of different amount of terminating hydrogen content of PDMS was studied.The results showed that the viscosity and molecular weight increased while the content of the terminating hydrogen decreased.2.The application of hydroxypropyl terminated silicone in anti-graffiti coatings.The coating was obtained from the mixing of PDMS-OH,hydroxylacrylic resin and curing agents.The paint was applied to the surface of glass/stainless steel,and the film properties after the curing at room temperature or by heat was tested,the result meets the customer's target requirements;and then all kinds of pens?aqueous,oily?were marked on the film surface.The graffiti were wiped off by cotton cloth with water,the resistance marker and anti-graffiti performance were investigated.3.Pilot-scale experiments of PDMS-OH.With the requirement of market and production,the PDMS-OH with common molecular weight 1900?wynca 2520?and 3400?wynca 2540?were scaled up to 500L.The reliability of the pilot-scale experiment was verified and the scale-up experience was collected.The results showed that the viscosity of PDMS-OH had more than 90%percent proficiency.The weight-average molecular weight was about 1900 and 3400 respectively,and the refractive index was 1.4122 and 1.4077 respectively.Compared with lab experiment,the properties were stable,the pilot-scale experiment was reliabiled.The manufacture technology,application research and pilot-scale experiment of PDMS-OH were determined through the above-mentioned work.And the PDMS-OH had good anti-graffiti effect in coating.