Tribological properties, polymers

In order to improve the tribological properties of molecular films, molecular surface modification is the first choice to make an approach. A Diblock polymer polystyrene-poly(ethylene)oxide (PS-PEO) thin-films were studied in our previous research because of its interesting structure (one... 

The implantation of low-to-medium energy ions changes only surfaee layer of polymers, with the thickness in nm-pm range, and preserves favorable bulk properties of polymers. By the ion implantation sueh surfaee properties as ehemieal strueture [108-111], wettability [109,110,112], eleetrieal eonduetivity [109,113-116], tribological properties [112,117,118] and bioaetivity [18,111-113,119] ean be ehanged in a manner which can be controlled by a proper ehoice of ion mass, energy and fluenee. 

Polymers were never intended to be bearing- or wear-resistant materials and in fact are usually unsuitable for tribological purposes. Hence, the number of polymers with valuable tribological properties is limited. Table 2 shows the most important polymers used for tribological applications along with their tribological characteristics [35]. 

Bermudez et al. [67] studied the tribological properties of PC+0.5%ZnO+1.5% IL composites and showed an 80% friction reduction and wear reduction of nearly two orders of magnitude with respect to PC+0.5% ZnO. They then investigated ILs as an effective lubricant additive of epoxy resin under the pin-on-disk configuration and showed a friction reduction higher than 50% and a wear rate reduction of two orders of magnitude for epoxy resin (RE)+1.5% IL with respect to the neat Re and Re+0.5% ZnO [68], The ability of ILs to act as lubricant additives of polymers under sliding conditions can thus be confirmed by the above report. 

Pei XW, Xia YQ, Liu WM et al (2008) Polyectrolyte-grafted carbon nanotubes synthesis, reversible phase-transition behavior, and tribological properties as lubricemt additives. J Polym Sci Polym Chem 46 7225-7237... 

Through plasma treatment, grafing of monomers can also take place on the polymer surface. For example, monomers, e.g., tetrafluoroethylene or hexafluoroethane, can be grafted onto wool or polypropylene fibers ( ). This type of grafting can improve such tribological properties as low friction. 

Any combination of the above two types of polymer can form thermoplastic IPNs in which some degree of dual-phase continuity is attained. Some of the thermoplastic IPNs have been claimed to be tough materials (44, 45). Though tribological properties of these new materials have not been investigated, they should be of... 

Recommendations MR 74-82. "Method for Estimation of Tribological Properties of Polymer-Based Materials",... 

Nishitani, Y. Ohashi, K. Sekiguchi, I. Ishii, C. Kitano, T. (2010). Influence of Additon of Styrene-Ethylene/Butylene-Styrene Copolymer on Rheological, Mechanical and Tribological Properties of Polyamide Nanocomposites. Polymer Composites, Vol.31, No.l, pp. 68-76 ISSN 0272-8397... 

In the last two decades, polymer nanocomposites have attracted the interest of researchers and industries because of their excellent mechanical, physical and tribological properties. The addition of nanosize inorganic fillers like clay, Al Oj, CaCOj, TiOj, ZnO and SiO has altered the mechanical and physical properties of the polymers significantly, and in general the nanocomposites are superior to virgin polymers in many aspects. 

Carbon-based polymer nano composites represent an interesting type of advanced materials with structural characteristics that allow them to be applied in a variety of fields. Functionalization of carbon nanomaterials provides homogeneous dispersion and strong interfacial interaction when they are incorporated into polymer matrices. These features confer superior properties to the polymer nanocomposites. This chapter focuses on nanodiamonds, carbon nanotubes and graphene due to their importance as reinforcement fillers in polymer nanocomposites. The most common methods of synthesis and functionalization of these carbon nanomaterials are explained and different techniques of nanocomposite preparation are briefly described. The performance achieved in polymers by the introduction of carbon nanofillers in the mechanical and tribological properties is highlighted, and the hardness and scratching behavior of the nanocomposites are also discussed. 

Keywords Nanodiamonds, carbon nanotubes, graphene, functionalization, polymer nanocomposites, mechanical properties, tribological properties... 

Tailoring the properties of polymers with the inclusion of nanometric carbon depends on many factors. Among them, the parameters most taken into account are (a) the size, structure and distribution of the nanofiller in the matrix and (b) the interface between the nanofillers and the matrix. This chapter focuses mainly on the effects that functionalization and concentration of nanofillers have in the storage modulus and tribological properties of polymer nanocomposites reinforced with NDs, CNTs and graphene, describing briefly the hardness and scratching performance achieved in these nanocomposites. 

A scratch test is an alternative to the conventional wear test to evaluate the tribological properties of polymers [75,100]. This test involves a high friction induced by a hard indenter which is pressed onto the material under load during the sliding process [51,150]. Briscoe et al. have provided a useful review about the most important theoretical models that have been developed in the field of scratching [179]. 

H. Chen, O. Jacobs, W. Wu, G. Rudiger, and B. Schadel. Effect of dispersion method on tribological properties of carbon njuiotube reinforced epoxy resin composites. Polymer Testing, 26 (3), 351-360,2007. 

L.F Giraldo, B.L. Lopez, and W. Brostow, Effect of the type of carbon njuio-tubes on tribological properties of polyamide 6, Polymer Enginering Science, 49 (5), 896-902, 2009. 

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