Fabrication of Orthotic Calipers With Epoxy-Based Green Composite

Introduction

Human race has been affected by disability of various forms such as vision impairment, mental disability, vision impairment, hearing impairment, speech disability, locomotive disability etc. Out of these the major disability is locomotive disability (related to ankle, foot, leg). The main cause of such disability in developing countries like India is polio. Polio is crippling and highly infectious disease caused by polio virus and the virus spreads from person to person due to which the amputees are unable to walk and move with their own. These amputees need a support with the help of which they could lead their lives easily. Researchers/scientists invented an appliance for those survivors which are known as braces/calipers. A brace or caliper helps in mobilizing or supporting a body part to assist the polio patients to undergo movement (Genet et al., 2010). Calipers or braces are categorized into three groups (Lower extremity, Upper extremity and spinal) taking into consideration the area affected and in which the patients require support. Calipers for lower body [Figure 1] rejuvenate weight bearing capabilities to the affected leg and hence allow the patients to walk without any risk of falling and contracture of joints (Hancox, 1982). It also provides support to the joints of affected organ and hence reduces joint pain. It also prevents further disfigurement of the joints and makes walking more effective by correct positioning of the calipers (Rao et al., 1985). Nowadays calipers, being designed by the designers, are effective and safer as they are being made considering patients work area, their age and weight. Currently it is required to be made as light and cheap as possible for increasing the ease of usage and also affordability to the general population (Sethi, 1990).

For creating a lighter caliper capable of taking the weight of affected patient, it is necessary to work with materials giving low weight to volume ratio. One of the most important and presently being used widely is composite materials. Composite materials provide low weight to volume ratio with strength when compared to many of the metals and alloys, hence, are being used extensively. Composite materials are made by combining of two or more unique materials having a distinct and identifiable interface segregating them. In tune to the major application, composites can be explained as those combinations of distinct materials that comprises of high strength/stiffness reinforcements embedded in a high performance matrix material (Thomason, 1995). The composites of interest in this work are materials possessing high strength and stiffness relative to weight comprising of natural fillers such as coconut coir dust. It is expected that the developed composites will have low weight to volume ratio, density, higher mechanical properties, specific tensile ratio (ratio of material strength to density), and higher versatility, less cost and can be machined very easily (Vignesh and Sengottaiyan (2014).

Figure 1.

Commercially available Orthotic Braces / Calipers

The natural filler composites, also known as green composites, have exhibited an increase of interest because of their disposal ease and abundant supply(Hossain, 2014).Inherent properties of natural filler composite, like light weight, low cost, renewable in nature, high specific strength and modulus, have enhanced their usage and offered a substantial reduction in the utilization of non-biodegradable polymers and non-recyclable resources(Biswas, 2012, Hossain, 2014, Ku et al., 2011, Lau et al., 2009, Rothon and DeArmitt, 2017, Verma et al., 2014).They are also offering much less abrasiveness than inorganic-mineral based composites to machines used for processing them and are naturally less harmful for the processing workers in case of exposure and above all they produce a final composite with lesser specific weight (in comparison to inorganic-mineral based composites)(Gnanasekar, 2015, Mohapatra et al., 2013).Additionally the natural filler based composite may be easily degraded at the end of their usage lifevia compositing or incineration in a furnace for reclamation of their calorific value which isn't feasible in inorganic-mineral based composites reinforced with fillers like glass (Kranthi and Sathapathy, 2010, Rathnakar and Shivanand, 2015).