PET薄膜的亲水改性研究

Hydrophilic Modification of PET Film

目的 探索对聚对苯二甲酸乙二醇酯(PET)薄膜亲水改性的制备工艺,研究其是否能有效提高PET薄膜表面的亲水性。方法 将PET薄膜裁剪成1 cm×4 cm的矩形样条,样条放入盛有无水乙醇的离心管中超声清洗,经烘干后再放入叔丁基过氧化氢(TBHP)溶液中进行引发反应,引发完成的PET薄膜样条依次用无水乙醇、水超声清洗后放入PVP溶液进行改性,最后超声清洗并烘干放置24 h进行接触角测试与红外光谱测试,分别评价PET薄膜的亲水性与表面成分变化。结果 使用不同PVP进行改性,PVP-K90对PET薄膜的改性效果最佳,接触角下降最明显,其接触角为21.3°。研究不同浓度TBHP对接触角的影响,随着TBHP浓度增加,接触角逐渐减小,TBHP浓度为1%时,其接触角为28°。探究不同浓度PVP-K90对接触角的影响,随着PVP-K90浓度增加,接触角呈现先减小后略有增大的变化趋势,PVP-K90浓度为5%时达到最小值(24.2°)。最佳配方和工艺为:5%PVP-K90+1%TBHP,温度80℃,转速600 r/min,反应时间1 h。PET薄膜的接触角从改性前的81.7°下降到改性后的29.5°,亲水性显著提高。亲水改性PET薄膜超声清洗20 min以上,接触角仍保持不变,红外光谱在3 427、1 608 cm^(-1)的特征峰明显增强,PVP以化学键合方式接枝在PET表面。结论 以TBHP作引发剂,PVP-K90作改性剂,通过表面接枝方法可有效提高PET薄膜的亲水性。

It is a hydrophilic modification method with simple process,good effect and cleaning resistance,which can effectively improve the hydrophilicity of the surface of the polyethylene glycol terephthalate(PET)film.Due to the defects of the existing PET hydrophilic modification methods,such as high equipment cost,complicated operation,this paper studies the use of polyvinyl pyrrolidone(PVP)as modifier and tert-butyl hydroperoxide(TBHP)as initiator for the shortcomings of the existing methods,the hydrophilicity of the PET film is significantly improved by grafting.Cut the PET film into a 1 cm×4 cm rectangle spline,put the spline into a centrifuge tube filled with absolute ethanol,clean it with an ultrasonic cleaner(SB-5200DTDN),and dry it in a vacuum drying oven(DHG-9075A).Put it into TBHP solution to initiate the reaction.The PET film strips that have been initiated are sequentially cleaned with absolute ethanol and water ultrasonically,and then put into PVP solution for modification.Finally,ultrasonically cleaned and dried for 24 hours using a contact angle measuring instrument(JC2000D1)and Fourier transform infrared spectrometer(TENSOR 27)to conduct contact angle test and infrared spectrum test to evaluate the hydrophilicity and surface composition changes of PET films respectively.First,the PET film is cut and pretreated with ultrasonic cleaning,followed by initiation and modification reactions;Second,during the initiation reaction,different amounts of TBHP(0%,1%,2%,3%,4%)were added,and the temperature-controlled magnetic stirrer(ZNCL-DB230)was used at 40℃and the rotation speed was 450 r/min with heating and stirring;Third,after ultrasonic cleaning,change the type of PVP(PVP-K17,PVP-K30,PVP-K90)and dosage(0%,2.5%,5%,7.5%,10%),the modification reaction is carried out under the condition of rotating speed 600 r/min,80℃,the final sample can be obtained by ultrasonic cleaning and drying and placing for 24 h.During the contact angle test of the sample,drop 2μL of water droplets on the sample to be tested at least at 5 different positions,read the static contact angle measured by the water droplets at each position,and take the average value;in the infrared spectrum test,after PVP drying in a vacuum drying oven at 50℃for 24 hours,the samples were prepared and tested by the tableting method.The PET and its hydrophilic modified samples were directly tested after being dried in a vacuum drying oven at 50℃for 2 hours.The measurement range was 400-4000 cm^(‒1) and the resolution was 2 cm^(‒1).PVP-K90 has the best modification effect on PET film,and the contact angle decreases most obviously,which is 21.3°.The effect of different concentrations of TBHP on the contact angle was studied.The contact angle decreased with the increase of TBHP concentration,and the contact angle was 28°when TBHP was 1%.The influence of different concentrations of PVP-K90 on the contact angle was investigated.With the increase of PVP-K90 concentration,the contact angle first decreased and then slightly increased,and reached the minimum value of 24.2°when PVP-K90 was 5%.The optimum formula and process were as follows:PVP-K905%,TBHP 1%,temperature 80℃,rotating speed 600 r/min and reaction time 1h.The contact angle of PET film decreased from 81.7°before modification to 29.5°after modification,and the hydrophilicity was significantly improved.The contact angle of the hydrophilic modified PET film remained unchanged after ultrasonic cleaning for more than 20 min.The characteristic peaks of the infrared spectra at 3427 cm^(‒1) and 1608 cm^(‒1) were significantly enhanced.PVP was grafted on the surface of PET in the form of chemical bonding.Therefore,using TBHP as initiator and PVP-K90 as modifier,the hydrophilicity of PET film can be improved by surface grafting.