Enhanced mechanical properties

As one example, in thin films of Na or K salts of PS-based ionomers cast from a nonpolar solvent, THF, shear deformation is only present when the ion content is near to or above the critical ion content of about 6 mol% and the TEM scan of Fig. 3, for a sample of 8.2 mol% demonstrates this but, for a THF-cast sample of a divalent Ca-salt of an SPS ionomer, having only an ion content of 4.1 mol%, both shear deformation zones and crazes are developed upon tensile straining in contrast to only crazing for the monovalent K-salt. This is evident from the TEM scans of Fig. 5. For the Ca-salt, one sees both an unfibrillated shear deformation zone, and, within this zone, a typical fibrillated craze. The Ca-salt also develops a much more extended rubbery plateau region than Na or K salts in storage modulus versus temperature curves and this is another indication that a stronger and more stable ionic network is present when divalent ions replace monovalent ones. Still another indication that the presence of divalent counterions can enhance mechanical properties comes from... 

Homogeneity of dispersion and the homogeneous nature of the hybrid ORMOSIL systems result in intensely coloured films even at low thickness. Compared to organic polymers, the coloured hybrid films have enhanced mechanical properties such as greater hardness and stronger abrasion resistance. With respect to inorganic sol-gel films, hybrid films also have several advantages such as much better adhesion,... 

Uses. Strontium master alloys are used in Al foundry practice. As an addictive to Al-Si alloys, it enhances mechanical properties and machining performance it modifies the morphology of the eutectic from coarse acicular plates of Si to a fine interconnected fibrous morphology, resulting in higher tensile strength and greatly improved ductility. 

To enhance mechanical properties and decrease wear, glass fibres are added to polymers but they are abrasive and attack the opposing surface. According to the circumstances they can also increase the coefficient of friction. 

These two are used either separately or as a mixture. Because of the presence of the somewhat flexible ethylene oxide and related units and use of appropriate fillers, these materials give composite fillings with lower polymerization shrinkage, enhanced mechanical properties, lower solubility and water adsorption, better thermal expansion characteristics, and good biocompatibility with aesthetic properties closely matching those of the tooth itself. 

Kushner AM, Gabuchian V, Johnson EG, Guan Z. Biomimetic design of reversibly unfolding modular cross-linker to enhance mechanical properties of 3D network polymers. J Am Chem Soc 2007 129 14110. 

The addition of OLDH as nanofiller in rubber must affect significantly the materials properties in comparison to the pristine polymer or conventional composites, including enhanced mechanical properties, increased heat resistance, and decreased flammability. 

The use of irradiated PTFE powder in EPDM gives enhanced mechanical properties as compared to composites containing nonirradiated PTFE. The existence of compatibility between modified PTFE powder and EPDM is indirectly revealed by , DSC, and SEM. shows that modified PTFE powder (500 kGy-irradiated) is obviously but partially enwrapped by EPDM as compared to nonirradiated PTFE powder. This leads to a characteristic compatible interphase around the modified PTFE. The resultant chemically coupled PTFE-filled EPDM demonstrates exceptionally enhanced mechanical properties. Crystallization studies by DSC also reveal the existence of a compatible interphase in the modified-PTFE-coupled EPDM. The synergistic effect of enhanced compatibility by chemical coupling and microdispersion of PTFE agglomerates results in improvement of mechanical properties of PTFE-coupled EPDM compounds. In summary, an effective procedure both for the modification of PTFE powder as well as for the crosslinking of PTFE-filled EPDM by electron treatment has been developed for the preparation of PTFE-coupled EPDM compounds with desired properties. 

PIB based thermoplastic poly(urethane)s (TPU)s have been synthesized. These composites exhibit enhanced mechanical properties. Poly(tetramethylene oxide) (PTMO) has been used as a compatibi-lizer. 

Qui, Y., and K. Park. 2003. Superporous IPN hydrogels having enhanced mechanical properties. AAPS Pharm Sci Technol 4 406... 

BN fibers are used for reinforcing ceramic materials (e.g., Al203, Si3N4, SiC) to enhance mechanical properties as well as to extend the range of possible applications. They serve as reinforcement of organic polymers (e.g., epoxides, polyether-polyketones, polyphenylensulfides) which exhibit good thermal conductivity and low thermal expansion. 

The initial interest in ceramic matrix nanocomposites arose from reports by Niihara and co-workers indicating enhanced mechanical properties due to the presence of ceramic (SiC) particles.53 With the development of various processing routes to introduce nanometer-sized metal particles in a ceramic matrix, variations in functional (i.e. magnetic) properties are possible. In the following we briefly review the microstructurally dependent properties, with emphasis on the possible mechanisms leading to improved properties and using SiC-reinforced alumina as a point of comparison. 

To date, few research groups have incorporated the enhanced mechanical properties of nanophase ceramics into orthopedic and dental applications. 

IPNs are also attractive for development of materials with enhanced mechanical properties. As PDMS acts as an elastomer, it is of interest to have a thermoplastic second network such as PMMA or polystyrene. Crosslinked PDMS have poor mechanical properties and need to be reinforced with silica. In the IPNs field, they can advantageously be replaced by a second thermoplastic network. On the other hand, if the thermoplastic network is the major component, the PDMS network can confer a partially elastomeric character to the resulting material. Huang et al. [92] studied some sequential IPNs of PDMS and polymethacrylate and varied the ester functionalities the polysiloxane network was swollen with MMA (methyl methacrylate), EMA (ethyl methacrylate) or BuMA (butyl methacrylate). Using DMA the authors determined that the more sterically hindered the substituent, the broader the damping zone of the IPN (Table 2). This damping zone broadness was also found to be dependant on the PDMS content, and atomic force microscopy (AFM) was used to observe the co-continuity of the IPN. 

Kanagaraj et al. (56) observed the enhanced mechanical properties with an increase of CNT concentration, which is believed to be due to good interface between polymer and CNT thus transferring load from the polymer to CNT and it is depicted in Table 5.5. It is observed from Figure 5.3 that the experimental relation between stiffness and... 

Their unique properties predestine them for both very specific applications and broad use in the field of polymer composites. They not only enhance mechanical properties but also electrical and thermal properties, act as flame retardants, etc. Thus their positives can be successfully exploited from simple or advanced polymer matrix reinforcement, through electronic devices, sensors and actuators, to electrorheological fluids, to name just the most important applications. 

Bates and coworkers have shown the enhanced mechanical properties of polymersomes compared to liposomes evaluated from different BC systems including poly(ethylene oxide)-b-poly(ethylene) (PEO-b-PE) and poly(ethylene oxide)-h-polybutadiene (PEO-h-PB) BCs with various block compositions [72]. Moreover, the... 

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