Preparation And Anticorrosive Performance Of TPU With Different Chain Extenders Strippable Films

Some raw metal materials and parts of an apparatus which needto be subsequent processed or assembled,are required to keep the surface clean.In order to protect these materials fromabrasion,wear,contamination and corrosion during its transportation and storage and remove protection when using materials,the use of anti-corrosion strippable films is the most effective,most convenient and economical way to solve this problem.Thermoplastic polyurethane?TPU?which can be heated and dissolved in solvent have been widely use inmany fields.The unique micro-phase separation structure of TPU with soft segment and hard segment makes it has adjustable mechanical properties,outstanding high elasticity,suitable adhesion,excellent resistance to chemical medium and corrosion resistance and so on.It is a great advantage that TPU can be used as a membrane material for anti-corrosion.In this study,the anti-corrosion strippable films with different corrosion inhibitor content are prepared by changing the structure of soft segment and hard segment of TPU.The influence of the change of TPU structure on the corrosion resistance and the strippable performance of the anti-corrosion strippable filmsare analyzed by the electrochemical test and salt water resistance test.It plays an important role in the development and application of a new type of anti-corrosion strippable films.It is of great practical significance to expand its application in the field of modern industrial anti-corrosion technology.The main contents and conclusions are as follows:?1?The different chain extenders of TPU?PT-TPU,PT-O-TPU,PT-S-TPU and PT-N-TPU?with polyoxytetramethylene glycol-1000?PTMG1000?as TPU soft segment,and 1,4-butanediol?BDO?,diethylene glycol?DEG?,diethylene glycol?TDG?and N-methyl two ethanol amine?MDEA?as chain extender and MDI as the hard segments is synthesized.The content of hard segments is 25%,30%,35%,40%and 45%in TPU.The number average molecular weight of different chain extender PT-TPU is above 30 thousand and the molecular weight distribution is narrow.With the increase of hard segment content,the crystallinity of PT-TPU,PT-O-TPU and PT-S-TPU increase,and the order of crystallization tendency is PT-S-TPU>PT-O-TPU>PT-TPU>PT-N-TPU?XRD?.The tensile results show that when the content of hard segment is low,the tensile strength and elongation of PT-TPU with different chain extender increases with the content of hard segment increasing,and when the hard segment content is 35%or 45%,elongation of PT-O-TPU is better than PT-TPU with other chain extender.The results of TG and DTG show that the thermal decomposition temperature ofPT-TPU with different chain extender when the content of the hard segmentis 35%is about 300?,which has good thermal stability.And the order of initial thermal decomposition temperature is PT-TPU>PT-O-TPU>PT-S-TPU>PT-N-TPU.?2?To change the soft segment,TPU with different chain extender?PE-TPU,PE-O-TPU,PE-S-TPU and PE-N-TPU?is synthesized with a wide range of sources,low price and the prospect of biodegradable polyethylene glycol-1000?PEG1000?as soft segments.The hard segment content is 30%,35%,40%,45%and 50%.The molecular weight of PE-TPU is 30 thousand and its distribution is small.And the molecular chain is uniform,which has little effect on the performance of PE-TPU.With the increase of hardness,the crystallization properties of PE-TPU is consistent with that of PT-TPU.Thermal performance results show that the order of initial temperature of PE-TPU with different chain extender which the content of hard segment is 45%is PT-S-TPU>PT-O-TPU>PT-TPU?PT-N-TPU.Compared with that of PT-PTU with different chain extender,the initial decomposition temperature of PE-TPU is lower,but the thermal decomposition temperature of the second stage is slightly higher.The electrochemical test results show that the corrosion resistance of PT-S-TPU is optimum because the E_corr of the PE-S-TPU film is the biggest,the i_corr is the smallest,and the Nyquist curve radius is the biggest.?3?The anticorrosive strippable films of PT-TPU/KD,PT-O-TPU/KD,PT-S-TPU/KD and PT-N-TPU/KD are successfully prepared by blending PT-TPU with different chain extenders and the content of hard segment is 35%and the environmentally friendly polymeric silicate powderwithout any filler metal?KD?as the corrosion inhibitor.And the content of KD is 0%,1%,3%,5%and 7%of PT-TPU with different chain extender respectively.The tensile strength and elongation at break of PT-TPU/KD anticorrosive strippable films decrease with the increase of KD,and the tensile strength and elongation at break of PT-O-TPU/KD are the highest.The order of 180°peel strength of PT-TPU/KD anticorrosive strippable filmswith different chain extender is PT-N-TPU/KD>PT-O-TPU/KD>PT-S-TPU/KD?PT-TPU/KD,PT-N-TPU/KD anticorrosive strippable films peeling is difficult.When the content of KD was higher than 5%,the corrosion resistance of the PT-TPU/KD film with different chain extender is better than that of the other one,and the corrosion resistance of PT-S-TPU/KD and PT-N-TPU/KD are the best.Electrochemical tests show that the corrosion resistance of PT-TPU films with different chain extender are improved after adding KD.Compared with the influence of different chain extenders,PT-S-TPU/KD has the best corrosion resistance.?4?In order to study the effect of different soft segments on the corrosion performance of strippable film,PE-S-PT-TPU/KD anticorrosive strippable films are successfully prepared by blending PE-S-TPU with the hard segment content is 45%and PT-TPU with different chain extendersand the hard segment content is 35%in different proportions and adding KD of 5%content.With the increase of content of PE-S-TPU,the tensile strength and elongation of PE-S-PT-TPU films decrease slightly,after adding KD,the tensile strength and the elongation of PE-S-PT-TPU/KD anticorrosive strippable filmsall decrease,meanwhile,the180°peel strength increase.After adding KD,tensile strength of PE-S-PT-TPU/KD anticorrosive strippable films increase,but the elongation decrease slightly,and with the average 180°peel strength increasing,filmsare stripped difficulty.When the PE-S-TPU:PT-TPU is 2:8,PE-S-PT-TPU films have good corrosion resistance,and after 30 daysbeing immersed in 3.5%NaCl solution,the surface of PE-S-PT-TPU/KD anticorrosive strippable films with different chain extenders have littlerusty spot and without foaming,whitening.Electrochemical tests show that when PE-S-TPU:PT-TPU is 2:8,the corrosion resistance of PE-S-PT-TPU/KD anticorrosive strippable filmsare the best,due to PE-S-TPU and KD PE-S-TPU and KD play a synergistic role in corrosion inhibition.The PE-S-PT-TPU/KD anticorrosive strippable films with different chain extenders show good thermal stability,at the same time,compared with the PT-TPU/KD anticorrosive strippable films with different chain extenders,the heat resistance of PE-S-PT-TPU/KD films are slightly decreased.