Reference	Research carried	Research outcome
Blau [8]	Reported on classification, typical properties and functions of various binders, fillers additives along with reinforcing fibers used in commercial brake materials formulation.	Role of each constituent in friction and wear control, and effect of their composition, form, distribution, and particle size was briefly discussed.
Bijwe et al. [9]	Reviewed on friction materials for automotive braking application, emphasizing development of semi metallic or resin bonded metallic and various fibers reinforced non-asbestos organics (NAO) braking materials.	New classes of non-asbestos fiber reinforced organic polymeric friction materials have completely replaced asbestos based brake materials because of their superior performance and their environmentally friendly nature.
Gurunath et al. [10]	Discussed about drawbacks of phenolic resin. In order to overcome this, an alternative resin was synthesized and tribo-tested to explore the possibility of replacing the currently used phenolic.	Composites prepared with new resin (N) proved better than the composite with traditional phenolic in all the tribo-performance properties.
Chan et al. [11]	Reviewed the various materials and constituents used in automotive brake friction material after the phasing-out of asbestos.	Mineral fillers (ceramic fillers) such as barite and clay are added to increase the volume as well as to reduce the overall cost of a composite on a volume basis.
Kim et al. [12]	The effects of reinforcing fibers on friction and wear characteristics were investigated with an emphasis on the friction film formation at the friction interface.	The friction film with both aramid pulp and potassium titanate maintained smooth friction surface and durable transfer film resulted in improved wear resistance and steady friction force.
Kato et al. [13]	The importance of friction modifiers in friction materials, such as abrasives and solid lubricants in achieving desired range of friction was discussed.	Functional fillers and inert fillers or space fillers can be used to reduce the cost without affecting functionality of the friction materials.
Tanaka et al. [14] Moraw et al. [15]	Proposed weight percentage of matrix, fiber and friction modifiers for polymeric friction composites.	Material comprising 5 wt% - 20 wt% binder resin, 10 wt% - 50 wt% carbon or aromatic polyamide fiber, 5?30 wt% solid lubricant and 5 wt% - 20 wt% ceramic powder exhibits stable friction force and excellent wear resistance
Ho et al. [16] .	Investigated on the effect of different short fiber reinforcement in friction materials.	Short fibers reinforcement, is most often used to obtain synergistic effect in mechanical and tribological performance of friction materials.
Friedrich et al. [17]	Investigated the influence of particle size and filler contents on the wear performance of nanoparticles reinforced thermoplastics and thermosets.	Presence of traditional fibers and/fillers with inorganic nanoparticles yields an optimal effect and showed a clear improvement in wear resistance of both thermosetting and thermoplastic composites.
Gopal et al. [18]	Analyzed the synergistic effect of multi-ingredients on friction and wear characteristics of friction materials.	Suggests that, the combination of several ingredients (fibers, micro/nano fillers and modifiers) and their synergism in a commercial friction material makes it rather difficult to analyze the friction and wear characteristics completely.