Polypropylene various properties

The first nanocomposite prepared by Toyota Group of Japan was based on nylon 6. In situ polymerization of caprolactum inside the gallery of 5% MMT resulted in the first nylon 6-clay nanocomposite. Besides nylon, polypropylene (PP) is probably the most thoroughly investigated system. Excepting the study of the various properties, theoretical aspects and simulations have also... 

It has been demonstrated in recent years that the nanotechnology can be applied to textiles to enhance various properties, especially in functional coatings, such as fabric softness, durability and breathability, water repellency, fire retardency, antimicrobial properties, anticrease properties, UV protection, self-cleaning properties and like in fiber, yarn and fabrics [131, 134-136]. Undyable polypropylene fiber can be made dyeable by... 

Table 2.2. Typical values for various properties of polyethylene and polypropylene. 

One unfortunate characteristic property of polypropylene is the dominating transition point which occurs at about 0°C with the result that the polymer becomes brittle as this temperature is approached. Even at room temperature the impact strength of some grades leaves something to be desired. Products of improved strength and lower brittle points may be obtained by block copolymerisation of propylene with small amounts (4-15%) of ethylene. Such materials are widely used (known variously as polyallomers or just as propylene copolymers) and are often preferred to the homopolymer in injection moulding and bottle blowing applications. 

Table 5 Effects of Various Phenolic Modified Polypropylenes on the Properties of NBR-Polypropylene Compositions Containing Amine Terminated NBR...

A polypropylene square slab, 0.3 m on a side, bums in a steady manner. Polypropylene does not char, and it can be considered that its radiation characteristics do not vary, with the flame radiative fraction at 0.38 and the flame incident heat flux to the fuel surface at 25 kW/m2. It burns in a wind as shown in various conditions as specified. Its convective heat transfer coefficient can be taken as 50 W/m2 K. The properties of polypropylene are listed as follows. 

All dendrimers consist of inner tertiary amines, located at the branching points of the various dendritic shells (layers). The amine-terminated dendrimers, furthermore, have basic primary amine end-groups. Basicity is therefore one of the most dramatic properties of the polypropylene imine) dendrimers, and has been studied via titration experiments and calculations. Titration experiments of the dendrimers have been performed in water using 1 M hydrochloric acid. Only two equivalence points are observed for DAB-J nJr-(NH2)4 in a ratio of 2 1. From these titrations, pKa values of 10.0 (primary amine groups) and 6.7 (tertiary... 

I believe we are just on the threshold of the C-13 NMR applications in studies of poljnner chemistry. Detailed structures are available for correlations with physical properties. Differences in configurational structure produced by various catalysts can be accurately determined. For eiample, the "irregularities" in crystalline polypropylene structure have been shown to be... 

In addition to the nature of particulate platelet orientation induced during injection moulding, the associated consequences on molecular orientation and crystalline order of the host thermoplastic matrix have also been reported with particular regard to various flake-filled polypropylenes [174], together with an attempt to interrelate these higher order structural parameters with physical properties of the composites [175]. 

Various types of well-defined block copolymers containing polypropylene segments have been synthesized by Doi et al. on the basis of three methods (i) sequential coordination polymerization of propylene and ethylene 83-m>, (ii) transformation of living polypropylene ends to radical or cationic ones which initiate the polymerization of polar monomers 104, u2i, and (iii) coupling reaction between iodine-terminated monodisperse polypropylene and living polystyrene anion 84). In particular, the well-defined block copolymers consisting of polypropylene blocks and polar monomer unit blocks are expected to exhibit new characteristic properties owing to the effect of microphase separation. 

Initially, conventional PCR tubes from various suppliers consisting, for example, of polypropylene or PVC with intentionally low proteinbinding capacities were used for IPCR [24, 29, 30, 41, 70]. As an alternative, polycarbonate TopYield modules (Nunc, Roskilde), specifically designed for IPCR applications with improved protein-binding properties, are increasingly popular as the material of choice for IPCR [26, 27, 34-37, 51, 62, 66, 67],... 

To further explore the influence of silica material properties (morphology, surface area, silanol concentration, and surface treatment) on the silica flame-retardant properties, various types of silicas (silica gel, fumed silicas, and fused silica) were investigated.50 51 Material properties of the various silicas are summarized in Table 8.6. These different types of silicas were added to polypropylene and polyethylene oxide to determine their flame-retardant effectiveness and mechanisms. Polypropylene was chosen as a non-char-forming thermoplastic, and polyethylene oxide was chosen as a polar slightly char-forming thermoplastic. Flammability properties were measured in the cone calorimeter and the mass loss rate was measured in the radiative gasification device in nitrogen to exclude any gas phase oxidation reactions. 

---