Montmorillonite-rich local bentonite was modified with four different quaternary alkyl salts: hexadecyltrimethylammonium bromide ((HMA)(Br)), tetra(kis)decylammonium bromide ((TKA)(Br)), tetrabutylammonium tetrafluoroborate ((TBA)(BF 4 )), and tetrabutylphosphonium tetrafluoroborate ((TBP)(BF 4 )) to produce organoclays. The organoclays produced were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), and x-ray diffraction (XRD). The XRD results indicate that the d-spacing of the organoclays increased as a consequence of the exchange of Na þ ions in the clay galleries with the cation of the surfactants with long alkyl tails. The d-spacing of the bentonite increased from 1.2 nm to 1.78 nm, 2.56 nm, 1.48 nm, and 1.64 nm after modification with HMA, TKA, TBA, and TBP cations, respectively. TGA analysis of the organoclays showed that the decomposition temperatures of the organoclays were higher than the melt processing temperature of polypropylene (PP), permitting the use of these organoclays in melt processing of PP. Ternary composites of PP/ PP-grafted maleic anhydride/organoclays were prepared using a twin screw extruder followed by injection molding for characterization. Transmission electron microscopy analysis of the composites showed intercalated structures as well as microcomposite

The use of modified bentonite as a reinforcement in polypropylene (PP)/organoclay/maleic anhydride grafted polypropylene (MAPP) nanocomposites was investigated. The modified bentonites (organoclays) were prepared from raw (unpurified) bentonite (RB) and two quaternary ammonium salts with long alkyl tails: hexadecyl trimethyl ammonium bromide [HDA][Br] and tetrakisdecyl ammonium bromide [TKA] [Br]. The ternary composites were produced by using a corotating twin screw extruder, followed by injection molding, and they exhibited microcomposite structure as observed by XRD. In order to observe the effects of purification of the bentonite, purified bentonite (PB) was obtained through sedimentation of raw bentonite, and later modified with two quaternary ammonium salts: dimethyl dioctadecylammonium chloride [DMDA][Cl] and [TKA] [Br], and one quaternary phosphonium salt: tributyl hexadecyl phosphonium bromide [TBHP] [Br]. Ternary nanocomposites (PP/organoclay/MAPP) with these organoclays were produced by using a corotating twin screw extruder, followed by batch mixing in an intensive batch mixer, and by injection molding. The use of [DMDA][Cl] and [TBHP][Br] resulted in nanocomposite formation, whereas the use of [TKA][Br] resulted in microcomposite formation as observed by XRD and TEM. Young's modulus of PP was increased by 30% with DMDA and 9% with TBHP. The yield strength of PP was increased by 15% with DMDA and 8.3% with TBHP.

The aim of this study is to analyze effect of four different isocyanates and four different plasticizers in hydroxyl‐terminated polybutadiene (HTPB) based elastomers by quantitative analysis of the shape of the loss factor (tan δ), tensile strength, deformation frequency shift of the maximum temperatures of loss moduli G" and of tan δ. The first part of the study shows intensities of the tan δ curves with the four isocyanates follow the order HDI > IPDI > H12MDI > Desmodur™ E305. By molecular modeling of the isocyanates and the corresponding polyurethane parts the influence of molecular geometry on tan δ are discussed. The second part of the study analyzes HTPB‐IPDI elastomers with the four different plasticizers DOA, DOS, DOZ, and IDP. The IDP provides lowest Tg at about −83°C, while the others provide at about −78°C. In the third part, aluminum (Al‐18 μm) and ammonium perchlorate (AP‐200 μm) are added to HTPB‐IPDI+DOA to analyze the effect of particle size, wt% content and particle type on the shape and intensity of the tan δ curves. From the frequency shift of the two maximum temperatures one receives activation energies Eaf. Their average values without and with plasticizer are with tan δ 178 and 165 kJ/mol and with G" 274 and 248 kJ/mol, respectively.

Polyethylene-based ternary nanocomposites were prepared with different clay structures, obtained by the modification of purified Resadiye bentonite as the reinforcement, a random terpolymer of ethylene, butyl acrylate, and maleic anhydride with the trade name Lotader3210 as the compatibilizer, and linear low-density polyethylene (LLDPE) as the polymer matrix in an intensive batch mixer. The quaternary ammonium/phosphonium salts used for the modification of bentonite were dimethyldioctadecyl ammonium (DMDA) chloride (Cl), tetrakisdecyl ammonium (TKA) bromide (Br), and tributylhexadecyl phosphonium (TBHP) Br. The effects of the physical properties and structure of the organoclay on the clay dispersion were studied at different clay contents (2 and 5 wt %) and at a compatibilizer/organoclay ratio of 2.5. The extent of organoclay dispersion was determined by X-ray diffraction (XRD) and was verified by transmission electron microscopy (TEM), mechanical testing, and rheological analysis. XRD analysis showed that the nanocomposite with the organoclay DMDA contained intercalated silicate layers, as also verified by TEM. The TEM analysis of the nanocomposites with TBHP exhibited intercalated/partially exfoliated clay dispersion. TKA, with a crowded alkyl environment, sheltered and hindered the intercalation of polymer chains through the silicate layers. In comparison to pure LLDPE, nanocomposites with a 33-41% higher Young's modulus, 16-9% higher tensile strength, and 75-144% higher elongation at break were produced with DMDA and TBHP, respectively (at 5 wt % organoclay). The storage modulus increased by 807-1393%, and the dynamic viscosity increased by 196-339% with respect to pure LLDPE at low frequencies for the samples with DMDA and TBHP (at 5 wt % organoclay).

Butacene® is a polymeric binder with ferrocenyl groups chemically bonded to HTPB backbone. Through incorporation in the AP−Al composite propellant formulation, it leads to high burning rates (BR) >20 mm/s at 7 MPa, and low pressure exponents n<0.5, allowing more flexibility to the rocket design, keeping the characteristics (process, mechanical properties, pot‐life) of HTPB binder formulations together with a lower vulnerability (IM) contribution by Butacene®. The key molecular level characteristic of such HTPB based elastomeric binder systems of solid composite rocket propellants (SCRP) is the glass‐rubber transition region, which is mainly defined by the molecular mobility of the components in the polymeric network during the transition from energy to entropy elasticity with respect to temperature. The molecular rearrangement regions or binder mobility fractions related to the glass‐rubber transition of such composite propellants during storage are important in terms of in‐service time estimations. They are detectable by dynamic mechanical analysis (DMA). Formulations with and without Butacene® were prepared and analyzed using the loss factor curves obtained by torsion DMA. A special modelling with so named Exponentially Modified Gaussian (EMG) distribution was used to define and quantify sub‐transition regions in the loss factor curve. SEM images revealed the network formation connected with AP bonding, which correlate to the tensile results. DMA loss factors revealed a strong oxidation with Butacene® containing formulations during aging. Burning rates of the formulations show slight increases with aging.