本文選題：超聲作用 + PP降解��； 參考：《華東理工大學(xué)》2016年博士論文

【摘要】：聚合物共混改性是聚合物高性能化的主要途徑之一,而熔融共混作為一種簡(jiǎn)單易行的共混改性方法,得到了廣泛的應(yīng)用。如何通過熔融共混強(qiáng)化改性劑在聚合物基體中的分散,提高基體樹脂的性能是目前共混改性領(lǐng)域關(guān)注的重點(diǎn)和熱點(diǎn)之一。作者通過在熔融共混中引入超聲作用,借助于超聲分散作用,改善了助劑在聚合物基體中的分散效果,達(dá)到提高共混物性能的目的。作者采用自制的超聲實(shí)驗(yàn)裝置,對(duì)超聲作用下聚丙烯(PP)的降解行為及其結(jié)晶性能進(jìn)行了研究。通過對(duì)特性黏度與分子量及其分布的測(cè)試,建立了超聲降解動(dòng)力學(xué)模型,研究了超聲頻率、功率、作用時(shí)間、作用距離及熔體溫度對(duì)PP降解的影響,并提出了超聲降解的機(jī)理。借助于廣角X射線衍射(XRD)、示差掃描量熱分析(DSC)及偏光顯微鏡等手段,對(duì)超聲作用下PP結(jié)晶行為進(jìn)行了深入的研究,揭示了超聲作用對(duì)PP結(jié)晶行為的影響規(guī)律。通過對(duì)樣品流變性能和力學(xué)性能的表征,研究了超聲作用對(duì)PP流變特性和機(jī)械性能的影響。作者針對(duì)超聲作用下氫化苯乙烯-丁二烯-苯乙烯嵌段共聚物(SEBS)在PP中的分散行為開展了研究。通過掃描電鏡分析(SEM)和理論推導(dǎo),建立了超聲分散破碎動(dòng)力學(xué)模型,并研究了影響分散相粒子超聲破碎的因素。借助于紅外光譜分析(IR)和動(dòng)態(tài)力學(xué)分析(DMA),對(duì)超聲作用下PP與SEBS原位增容效應(yīng)進(jìn)行了研究。通過對(duì)樣品流變性能和力學(xué)性能的表征,研究了超聲作用對(duì)PP/SEBS共混物流變特性和機(jī)械性能的影響。作者采用超聲輔助雙轉(zhuǎn)子連續(xù)混煉的方法,制備PP/SEBS/有機(jī)蒙脫土(OMMT)三元納米復(fù)合材料。通過小角XRD、透射電鏡分析(TEM)和SEM等表征方法,研究了超聲作用和相容劑馬來酸酐接枝聚丙烯(PP-g-A)對(duì)復(fù)合材料微觀分散形態(tài)的影響。借助于廣角XRD分析,研究了超聲混煉作用下復(fù)合材料的結(jié)晶性能。通過對(duì)樣品流變性能和力學(xué)性能的表征,研究了超聲作用和PP-g-MA對(duì)復(fù)合材料流變特性和機(jī)械性能的影響。研究工作得出以下幾點(diǎn)創(chuàng)新性結(jié)論：(1)在超聲樣品中觀察到空化泡,并提出空化作用是造成超聲作用下PP降解的主要原因之一。空化作用越強(qiáng),PP的降解程度越高。隨著超聲功率和超聲作用時(shí)間的增加,超聲空化作用增強(qiáng),PP的降解程度增大。但是,隨著超聲功率和作用時(shí)間的進(jìn)一步增加,PP的降解程度減小,其分子量和特性黏度最終趨于一個(gè)極限值。此外,在20KHz(低頻率)的超聲作用下,PP熔體中的空化效應(yīng)最明顯,在此頻率下的降解行為也最顯著。(2)適當(dāng)強(qiáng)度的超聲作用可誘導(dǎo)β晶型PP的形成,但超聲強(qiáng)度過高會(huì)導(dǎo)致PP的大幅降解而不利于β-PP的結(jié)晶。(3)建立了聚合物兩相共混物中分散相顆粒的超聲破碎動(dòng)力學(xué)模型及破碎速率動(dòng)力學(xué)模型提出增大超聲功率、降低超聲頻率和降低熔體溫度均可提高分散相顆粒的破碎程度,并且距離超聲源較近處,分散相顆粒的破碎程度較高。(4)在超聲作用下PP與SEBS會(huì)發(fā)生共聚反應(yīng)而使其相容性得到提高,適當(dāng)提高超聲強(qiáng)度會(huì)促進(jìn)反應(yīng)過程的進(jìn)行,但是過高的超聲強(qiáng)度會(huì)因?yàn)榫酆衔锏拇蠓到舛焕谠鋈葸^程。(5)首次采用超聲輔助雙轉(zhuǎn)子連續(xù)混煉方法制備PP/SEBS/OMMT (95/15/5)三元納米復(fù)合材料。經(jīng)歷超聲輔助共混的復(fù)合材料的沖擊強(qiáng)度較純PP提高了80.9%,較未經(jīng)超聲輔助混煉的復(fù)合材料提高了7.9%,達(dá)到49.2J/m；添加15ph的PP-g-MA并經(jīng)歷超聲輔助共混的復(fù)合材料的拉伸模量較純PP提高了24.8%,較未經(jīng)超聲輔助混煉的復(fù)合材料提高了84.8%,達(dá)到913.6MPa。
[Abstract]:Polymer blending modification is one of the main ways of high performance of polymer, and melt blending, as a simple and easy method of blending modification, has been widely used. How to strengthen the dispersion of the modifier in the polymer matrix by melt blending and improve the properties of the matrix resin is the focus and heat in the field of blending modification at present. One of the points. Through the introduction of ultrasound in melt blending, the author improves the dispersing effect of the additives in the polymer matrix by ultrasonic dispersion and improves the properties of the blends. The author studied the degradation behavior and crystallization properties of polypropylene (PP) under ultrasonic action by using the self-made ultrasonic apparatus. After testing the viscosity and molecular weight and its distribution, a kinetic model of ultrasonic degradation was established. The effects of ultrasonic frequency, power, action time, action distance and melt temperature on the degradation of PP were studied, and the mechanism of ultrasonic degradation was put forward. By means of wide angle X ray diffraction (XRD), differential scanning calorimetry (DSC) and polarizing microscope, etc. The crystallization behavior of PP under ultrasonic action was deeply studied. The influence of ultrasonic action on the crystallization behavior of PP was revealed. The effects of ultrasonic action on the rheological properties and mechanical properties of PP were investigated by the characterization of the rheological and mechanical properties of the samples. The dispersion behavior of the segment copolymer (SEBS) in PP was studied. By scanning electron microscopy (SEM) and theoretical deduction, the ultrasonic dispersion fragmentation kinetic model was established and the factors affecting the ultrasonic fragmentation of the dispersed phase particles were studied. With the aid of infrared spectroscopy (IR) and dynamic mechanical analysis (DMA), the in situ Compatibilization of PP and SEBS under ultrasonic action was carried out. Effects were studied. Through the characterization of the rheological and mechanical properties of the samples, the effects of ultrasound on the rheological properties and mechanical properties of PP/SEBS blends were studied. The author uses the ultrasonic assisted double rotor continuous mixing method to prepare the PP/SEBS/ organic montmorillonite (OMMT) three element nanocomposite. Through the small angle XRD, transmission electron microscope The influence of ultrasonic action and compatibilizer maleic anhydride grafted polypropylene (PP-g-A) on the microdispersion of the composites was studied by means of (TEM) and SEM characterization methods. The crystallization properties of the composites were studied with the aid of wide angle XRD analysis. The ultrasonic effect was studied by the characterization of the rheological and mechanical properties of the samples. The effects of PP-g-MA on the rheological properties and mechanical properties of the composites are obtained. The following innovative conclusions are obtained: (1) the cavitation bubbles are observed in the ultrasonic samples, and the cavitation effect is one of the main reasons for the degradation of PP under ultrasonic action. The stronger the cavitation effect, the higher the degradation degree of PP. With the increase of time, the effect of ultrasonic cavitation increased and the degree of degradation of PP increased. However, with the further increase of the ultrasonic power and time, the degradation degree of PP decreased, and the molecular weight and characteristic viscosity eventually tended to a limit value. In addition, the cavitation effect in the PP melt was the most obvious under the 20KHz (low frequency) supersonic effect, and the frequency of this frequency was the most obvious. The degradation behavior is also the most significant. (2) the proper intensity of ultrasound can induce the formation of beta crystalline PP, but the high ultrasonic intensity will lead to the degradation of PP and the crystallization of beta -PP. (3) the ultrasonic fragmentation kinetics model of dispersed phase particles in the polymer blends and the kinetic model of breaking rate have been established to increase the ultrasonic power. The fragmentation degree of dispersed phase particles can be increased by reducing the ultrasonic frequency and reducing the melt temperature, and the fragmentation degree of the dispersed phase particles is higher than the ultrasonic source. (4) the compatibility of PP and SEBS will be enhanced under ultrasonic action, and the proper enhancement of ultrasonic intensity will promote the process of reaction. The high ultrasonic intensity will not benefit the compatibilization process because of the large degradation of the polymer. (5) the ultrasonic assisted double rotor continuous mixing method is used for the first time to prepare PP/SEBS/OMMT (95/15/5) three element nanocomposites. The impact strength of the composite with ultrasonic assisted blending is 80.9% higher than that of the pure PP. The material increased by 7.9% to 49.2J/m, and the tensile modulus of the composite added with 15ph PP-g-MA and through the ultrasonic assisted blending was 24.8% higher than that of pure PP, and the composite improved by 84.8% to 913.6MPa. without the ultrasonic assisted mixing.
【學(xué)位授予單位】：華東理工大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：TQ325.14;TB33

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