Preparation Of New Polyurethane Elastomer Damping Materials By Anioninitiator With Protective Group

Damping materials can convert mechanical vibration energy into heat and dissipate it,and play a role in reducing vibration and noise.It is widely used in bridge isolation bearings,precision instrument vibration damping parts,and acoustic coating of submarine.In the development and application of damping materials,polymer materials have always played an important role in the field of damping due to their unique viscoelasticity and excellent processability.Polyurethane is structurally designable,and styrene-butadiene rubber has an adjustable number of vinyl and benzene rings,which are two important polymer damping materials.Combining the damping advantages of the two,the paper uses the protective group initiator 3-(tert-butyldimethylsiloxane)-1-lithiumpropane,and anion method to synthesize hydroxyl-terminated solution polymerized styrene butadiene rubber(HTSSBR),And as the soft segment of polyurethane,use p-phenylene diisocyanate(PPDI),1,4-butanediol(BDO),1,1,1-trimethylolpropane(TMP)as the hard segment of polyurethane,and synthesize hydroxyl by prepolymerization.End-capped solution polymerized styrene butadiene rubber-polyurethane(HTSSBR-PU).The influence of factors such as the ethylene content,molecular weight,and hard segment content of HTSSBR on the structure and performance of HTSSBR-PU has been studied.The main research results are as follows:In Chapter 3 of this paper,a series of HTSSBRs with different glass transition temperatures(Tg)were prepared using self-made protective group initiators.Control the styrene content of 25%,the molecular weight of 5000,and adjust the polarity regulator tetrahydrofuran(THF)content,that is,R=([THF]/[Li])value.When R increases from 0 to 25,the vinyl content of HTSSBR is changed from 10%increased to 69%,the corresponding Tg increased from-81.2? to-15.5?;controlled R=15,molecular weight 5000,adjusted the feed ratio of butadiene and styrene,the styrene content of HTSSBR increased from 25%to 50%,the corresponding Tg increased from-24.3? to0.4?;control R=15,styrene content 30%,adjust the initiator content,the molecular weight of HTSSBR increased from 2000 to 10,000,the corresponding Tg increased from-18.8? increased to-14.3?.In Chapter 4 of this paper,the influence of vinyl content,molecular weight and hard segment content of HTSSBR on the properties of polyurethane is discussed.Control the styrene content of 25%,the molecular weight of 5000,and the hard segment content of 25%.When the vinyl content of HTSSBR increases from 35%to 69%,the Tg of HTSSBR-PU increases from-55.19? to-10.05?;the maximum loss factor(tan?max)From 1.06 to 1.33,the temperature corresponding to the maximum loss factor(Tg(tan?max))increases from-40?to-3?;the crystallinity is about 4%;the tensile strength is about 6.4MPa.The increase of vinyl content in HTSSBR is beneficial to increase the loss factor of HTSSBR-PU.Control R=15,styrene content 30%,hard segment content 25%,when the molecular weight of HTSSBR increases from 2000 to 10,000,the Tg of HTSSBR-PU decreases from-7.07? to-21.71?;the average size of the hard segment increases from 81nm to 183nm;crystallinity increased from 3.56%to 5.26%;tan?max increased from 0.61 to 1.39,Tg(tan?max)decreased from 10.4?to-3.2?;tensile strength decreased from 12.3MPa to 7.8MPa.The increase in the molecular weight of HTSSBR is beneficial to increase the loss factor of HTSSBR-PU.Control R=15,styrene content 30%,molecular weight 5000,when the hard segment content increases from 25%to 45%,the Tg of HTSSBR-PU basically does not change;the average size of the hard segment increases from 116 nm to 238 nm;crystallinity The temperature increased from 3.68%to 6.37%;the tan?max decreased from 1.40 to 0.99,the Tg(tan?max)increased from 6.7? to 8.3?;the tensile strength increased from 12.0MPa to 14.9MPa.HTSSBR-PU with a hard segment content of 25%has both excellent damping properties and good mechanical properties.