Composites are combination of two materials that provide characteristics not obtainable from any discrete material. X-ray opacity is required in medical devices such as catheters, tubing’s, body implants, dental products .Thermoplastic polymer is used widely in manufacturing medical devices because of their unique characteristics. Barium sulphate is selected as a filler material because it is inert, resistant to acid and alkalis, and has good weathering resistance. Its dispersibility is high; hardness and stiffness of plastics are improved without effect on surface quality (especially gloss and color brilliance). It is also used to increase X-ray opacity, especially for medical devices. Thermoplastic polymers/ Barium Sulphate composites thus prepared can be used in applications where radiopacity is of prime importance.

Abstract

Radiopaque barium sulphate filled thermoplastic polymers are widely used in the medical device industry. Barium sulphate (BaS04) is in a group of drugs called contrast agents. Barium sulphate works by coating the inside the stomach or intestines which allows them to be seen more clearly on a CT scan or other radiologic (x-ray) examination. Barium sulphate is used to help diagnose certain disorders of the stomach or intestines. Increasing wt% of BaS04 with specified polymer is mixed in a twin screw extruder. The granules of the composites thus obtained are injection molded and tested for X-ray opacity and it is expected that the X-ray opacity increases with the increase in the content of BaS04 in the polymer. Increasing the X-ray opacity in these polymers will help to trace the medical devices in the body and help placing them in exact location wherever it is needed.

Keywords: Barium sulphate, X-ray opacity, polymer, composites.

Corresponding author: Email Id Subhasch.shit@yahoo.com , giripolymer@gmail.com

Introduction

A medical device is anything used for therapeutic and/or diagnostic purposes in humans or animals, which is not a drug. They can be classified into two categories - disposables and nondisposables. Materials used in design, production and assembly of medical devices include metals, ceramics, glass and plastics. Plastics have superior design flexibility compared to metals, ceramics and glass. The products made from plastics can be made into different shapes, sizes, thickness and color to meet the physical, mechanical, chemical and biocompatibility requirements. Plastics can be processed by various processing techniques with the addition of fillers and additives. One of the requirements for medical devices used for diagnostic and other interventional surgical

procedures is clear visibility under X-Ray. Barium sulphate is a radiopaque additive obtained from naturally occurring mineral known as Blanc Fixe having an average particle size less than 2 micrometers. It is a white powder used as a filler because of its unique characteristics like X-Ray opacity, specific gravity, frictional resistance, chemical resistance. Depending on the types of applications, the criteria for radiopacity are different. For applications near the surface skin, devices with low radiopacity are required but for applications like intravenous or cardiovascular procedures, the devices have to be inserted deep into the body and so much higher radiopacity is required. In the application of intravenous catheters, barium sulphate is added to the bulk polymers to make the catheter inside the blood vessels visible by X-Ray [1-10]. The current article deals with making a radiopaque composite by mixing barium sulphate as a filler with a thermoplastic polymer with different wt% compositions of the filler into the thermoplastic polymer matrix and preparing a composite with different X-Ray opacities. The composites thus prepared are tested for different physical, mechanical, thermal and X-ray opacity tests to decide the area of used of the final X-ray opaque medical device.

Composites

They are combinations of two materials in which one of the materials, called the reinforcing phase, is in the form of fibers, sheets, or particles, and are embedded in the other material called the matrix phase. The matrix material can be metal, ceramic, or polymer.

Broadly, composite materials can be classified into three groups on the basis of matrix material.

Advantages of Composite Materials

• Tensile strength of composites is four to six times greater than that of steel or aluminum.

• Weight savings are significant, frequently ranging from 25 to 50% of the weight savings can be achieved over conventional metallic designs.

• Corrosion resistance is outstanding.

• Good fatigue and fracture and impact resistance.

• Flexibility in selection or changing of styling and product aesthetic features. Modifications in response to changing customer needs can be made with limited investment.

• Like metals, thermoplastics have indefinite shelf lives.

• Manufacturing and assembly are simplified because of part integration which can reduce engineering, purchasing, and follow-up costs.

Polymer Matrix Composites

A composite in which the matrix is either thermoplastic or thermoset polymer or the reinforcement is in fibrous form (Glass, carbon, aramid, natural fibers) or particulate form (Macro, micro or nano sized particles) is called polymer matrix composites.

Fillers

The term filler refers to any type of low cost additive which is used to simply increase bulk and reduce cost of the compound additive. They are used to cheapen or extend a product with an evident change or modification of the properties of the unfilled materials such as hardness, rigidity, viscosity or color.