Processing-structure-property relationships in (TPE-E) nanocomposites Lab Report

Processing-structure-property relationships in (TPE-E) nanocomposites - Lab Report Example This area of research is extremely promising because such systems possess higher dispersion then conventional organolclays do. Also, it is worth mentioning that examples from both literature and experimentaly achieved data point out that alkyl-ammoniums used as organo-modifiers have limited applications for apolar polymers. Scheme 1: Alkyl-ammoniums used as organo-modifiers For such polymers interactions with clay is usually low and further entropic barriers prevent mixing of an inorganic clay with the desired polymer. In other words, alkyl chain-clay interactions are low. To overcome this organo-modifiers are used but, as our studies suggest, low thermostability (Changes in composition start to occur at approx. 2200C) of the produced modified clay will limit the scope of potential applications. 4.1 Modification of Clay As it was previously stated, it was necessary to modify Fluormica (Somasif ME 100) Prestine clay to increase its mixability with the polyester TPE. The employed type of clay is hydrophilic. This factor contributes to poor solubility in hydrophobic polymers. It terms of structure, Fluormica (Somasif ME 100) is made of layers which are held together by electrostatic forces. These layers carry the negative charge, while positively charged cations are shared equally between stacks of layers. This structure is not easy to brake, what is another factor to poor mixability. In order to modify the studied clay ion exchange reactions were used. The chemical formulation is Na0.66Mg2.68(Si3.98Al0.02)O10.02F1.96 [65] and the particle size is about 650 nm. (Cation Exchange Capacity is 100 mequiv/mol). Thus it can be presumed that cations such as Na+ and Mg2+ can be substituted by an alkyl-ammonium (Scheme 1) cations. Alkyl-ammoniums carry different hydrophobic groups consequently, producing various hydrophobicity. Hydrophobic chain makes the modified clay more compatible with the organic matrix. Employing different alkyl-ammoniums it will be possible to mak e the clay compatible with almost any required polymer. Moreover, treatment with described organic modifiers will separate clay plates. This will afford intercalated and exfoliated materials which can be used to produce nanoparticles. To describe the produced modified clay it is necessary to analyse Fourier transform infrared spectrosctrum(FT-IR) then move on to X-ray photoelectron spectroscopy (XPS) before finally commenting on thermogravimetric analysis (TGA) curves. 4.2 FT-IR The major peak for all the studied samples occurs at 902 cm-1 (Scheme 2). This wavelength can be associated only with carbon-oxygen-carbon symmetric stretch absorbtion. There is only one peak in this region there are no peaks formed by asymmetric carbon-oxygen-carbon absorbtion. The next major peak occurs at 2925 cm-1 but not for all studied entries. ME 100 and ME100 CC do not possess such peak. The formed peak is due to asymmetric stretch of CH2-O group. The described peaks prove the presence of specific bo nds in the molecule. Scheme 2: FT-IR spectrums of the modified clay samples. 4.3 XPS On the Schemes 3 and 4 ME 100 is the unmodified clay and all the entries from 2 to 8 present various modifications. It is seen that not all Na+ and Mg2+ are substituted by N+R4. In ME 75 Etho substitution is the most efficient and ME 100 CC shows only slight reduction on Na+ and Mg2+ quantity. No Sample Code O (%) C