奈米級黏土運用於PU 複合材料發泡體(foam) 及薄膜(film)之製備及其性質研究

The Study of Preparation and Properties of the Nanocomposites Foams and Films based on PU and Nano-clays

楊行中(Hsing-Chung Yang)

指導教授 ： 陳玉惠

中原大學/理學院/化學研究所/博士(2004年)

https://doi.org/10.6840/cycu200400475

摘要

摘要
本論文主要以奈米級黏土（Clay）應用在PU高分子發泡體（foam）及薄膜（film）之製備及其性質研究上。其內容分為發泡體及薄膜二部分。發泡體部分先選用黏土PK805、PK802、PK811及PK812，分別以四級胺鹽改質劑，dilaurydimethylammonium bromide[CH3(CH2)11]2N(CH3)2Br，(LD)及caprolactone CH2(CH2)5CO，
O
(CPL) ，以陽離子交換方式進行改質作用，而得有機性黏土Clay11，
Clay12，Clay22，Clay51及Clay52等五種。由X-射線繞射（XRD）測試得知不同改質劑對不同黏土產生不同的層間距離，例如：LD改質劑具有長鏈的結構，立體空間較大，所以在改質作用進行陽離子交換時（cationic-exchange）將黏土（PK805）矽酸鹽類層間距離（d-spacing）由原先1.13nm擴增至2.44nm（Clay51），而CPL則將PK805黏土的矽酸鹽類層間距離（d-spacing）由原先的1.13nm增加至1.44nm（Clay52）。這些不同的改質黏土與PU高分子混摻（blending）時，PU高分子鏈均插層於黏土層間，但分散情形亦不盡相同。
利用Clay11，Clay12，Clay22，Clay51及Clay52五種不同黏土分別以1 wt%、3 wt%、5 wt%等不同比例的添加量加至PU高分子主體中製備PU/clay奈米級複合材料發泡體。由硬度測試結果顯示當clay添加量增加時，其密度隨之增加，但硬度則因插層作用而逐漸降低。紅外線光譜（FT-IR）顯示出本研究製備之發泡體中黏土與PU高分子體間只有單純的插層作用，沒有任何鍵結產生。由機械性質測試得知當黏土添加量增加時，其Modulus，Elongation，Tensile strength均下降，說明了層狀的矽酸鹽類因為插層作用而破壞了PU 發泡體的網狀結構。而從熱性質測試結果顯示隨著clay含量的增加，其難燃性及耐熱性均會提升。LOI測試結果奈米黏土分散在高分子複合材料中對防火性有明顯的改善，當黏土含量增加，無機層狀的矽酸鹽類燃燒時易形成碳化層以阻絕外在氧氣進入，降低燃燒速率而達到自熄效果。熱傳導測試結果亦顯示，奈米黏土添加量的增加可減少熱的傳導性質。
薄膜部分則是將黏土（PK805）以兩種不同的四級胺鹽， dilaurydimethyl ammonium bromide （LD）,及4,4-diaminodiphenylmethane(AP)，改質為具有有機性的黏土LDM及APM。再於適量的PPG、TDI及1,4-butandiol合成PU高分子的過程中，加入不同比例的LDM與APM，製備出PU/LDM與PU/APM二種PU奈米複合材料薄膜。利用X-Ray diffraction (XRD)圖譜及穿透式電子顯微鏡Transmission electronic microscopy (TEM)檢視改質過的黏土層在PU高分子薄膜中之插層狀況，發現這些奈米黏土係以插層(intercalation)或剝離(exfoliation)兩種形式分散於PU高分子主體中。
以混摻奈米級黏土（nano-clays）的PU奈米複合材料與純的PU高分子薄膜相比，由DSC、TGA及LOI量測可以得知PU/Clay奈米複合材料之熱安定性及難燃性均隨著改質過之有機性Clay的量增加而提升。另使用Tafel方法進行電化學的腐蝕電位(Ecorr ，corrosion voltage)、極化阻抗(Rp，Polarization resistance)及腐蝕電流 (Icorr，corrosion current) 量測，得知以少量的PU/Clay奈米複合材料塗抹在不鏽鋼（stainless steal disk，SSD）材料上時，其抗腐蝕性明顯增加。以2 wt% APM與PU混摻後所得之PU/APM2奈米複合材料塗佈在SSD上可得最低之腐蝕速率(Rcorr，corrosion rate)，較純PU塗佈在SSD上低一個級數(one order)以上，顯示本研究製備之PU/Clay奈米複合材料運用在抗腐蝕性 (anti-corrosion)上極具功效。

關鍵字

發泡體 ； 奈米黏土 ； 薄膜 ； 複合材料

並列摘要

The aim of the present work is to prepare nanocomposites of PU/Clay foam and films by adding nanosized clays into polymer matrix and study their characteristics. The content of this work is divided into two parts.
In the first part, hydrophilic clay pk805, pk802, pk811, pk812 were modified with quaternary ammonium salts of dilaury (dimethylammonium bromide [CH3(CH2)11]2N(CH3)2Br (LD) and caprolactone CH2(CH2)5CO
O
(CPL) , obtaining five corresponding organophilic clays clay11, clay12, clay22, clay51, and clay52.
The X-Ray diffraction result showed that the modification was dependent on the structure of the modifier. By using LD modifier, the nanolayer of silicate d-spacing was increased to 2.44nm from its original value of 1.13nm (Clay51), but, in the case of using CPL modifier the d-spacing only increased from 1.13nm to 1.44nm (Clay52). The five as-prepared organophiic clays (clay11, clay12, clay22, clay51, clay52), with the ratio of 1 wt% or 3 wt% or 5 wt% increment were separately dispersed into the PU polymer matrix to form the corresponding PU/Clay nanocomposite foams.
X-ray diffraction(XRD), scanning electron microscopy(SEM), Fourier transform infrared spectrometer(FT-IR), density, hardness, isothermal conductivity, limit oxygen index(LOI), differential scanning calorimetric(DSC), thermal gravemetric analysis(TGA) and tensile testing measurements were performed to characterize the physical properties of the as-prepared nanocomposites of PU/Clay foams.
The results indicated that the density of the nanocomposite PU/clay foam was increased with the amount of clay content, but the hardness was decreased due to the intercalation. The FT-IR spectra showed that only simple intercalations with no bonding formation was revealed between clay in the polymer matrix.
From the mechanical studies, it was found that the modulus, elongation and the tensile strength were decreased as the clay content increased. This suggested that the intercalation of layer silicates disrupted the network structure of the PU foam. The thermal analyses and thermal conductivity measurements showed that the heat-resistance and thermal conductivity were elevated with the increase of clay content. The LOI values and the char yields formed were also increased with increasing of the clay in the burning state. Implying that the dispersion of nanoclays in the polymer matrix obviously increased the anti-fire properties of the PU polymer composite foams prepared.
In the second part, the principle purpose is that the montmorillonite clay was modified with two different quaternary ammonium salts, dilauryldimethylammonium bromide [CH3(CH2)11]2(CH3)2NBr (LD) and 4,4’-diaminodiphenyl methane H2NC6H4CH2C6H4NH2 (AP), to form the corresponding organophilic clays, LDM and APM. Two series of PU/clay nanocompositie materials were then prepared by the reaction of appropriate amounts of PPG, TDI and 1,4 butandiol, followed by addition of the modified clays. The X-ray diffraction patterns and transmission electron micrographs of the nanocomposites revealed that the modified clay galleries were exfoliated or intercalated in the polyurethane matrix. In comparison with the corresponding pristine PU, it was found that the PU/clay nanocomposites showed higher glass transition temperature and thermal stability due to the presence of the dispersed nanolayers of the organophilic clay in the PU matrix. The LOI measurements indicated that the flame retardancy of the PU was also enhanced by dispersion of the organophilic clays. Using the Tafel method, the results of the electrochemical measurements, corrosion potential, polarization resistance and corrosion current, showed that all the PU nanocomposites with low clay loading in the form of coating on stainless steel disk (SSD) exhibited better corrosion protection over the pristine PU. The SSD coated with the composite containing 2 wt% of APM clay showed the lowest corrosion rate, which was one order lower than that of the SSD coated with the pristine PU.

並列關鍵字

polyurethane ； PU/Clay ； nanocomposite ； PU

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