Polymers
- Submitted by: manasprotim9
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- Category: Science
- Date Submitted: 05/08/2011 11:58 PM
- Pages: 2
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Advancement of polymer science is one of the most significant contributions of Chemistry for the welfare of humankind in the last century. From disposable wrappers to the artificial heart; polymer touches our lives as does no other class of material, with no end to new uses and improved products in sight. Now-a-days it is almost impossible to imagine a world without polymers.
Polymers or macromolecules or high polymers or giant molecules are high-molecular-weight materials composed of repeating subunits called monomers. These materials may be organic, inorganic or organometallic and synthetic or natural in origin. Polymers are essential materials for almost every industry as adhesives, building materials, paper, cloths, fibers, coatings, plastics, ceramics, concretes, liquid crystals, photo resists coatings etc. They are also major components in plant and animal body. They are important in nutrition, engineering, biology, medicine, computers, space exploration, healthcare and the environment. The first synthetic polymer was produced in 1909; called Bakelite which could be moulded at a high temperature and it would retain its shape once cooled. But it wasn't until the World War I that significant changes took place in the polymer industry. Synthetic polymers have found wide spread application because of their low density, low cost and better performance.
The term nanocomposites means to distribute as much as possible amounts
of nanoparticles in a polymer matrix. It has been shown that, when using fiberreinforced
polymers, the maximum amount of fibers in the matrix is about 70 vol.%.
Actually, the fiber volume fraction in these materials varies between 20 and 60%.
Figure 1 summarizes the values to be achieved for various fillers used in composites.
In a volume element of 1 cm3, it was assumed that we have continuous fibers with
a diameter of 10 pm, particles (e.g., talcum) with a diameter of 1 pm, and nanotubes
with a diameter of 10 nm. The aspect ratios...
Polymers or macromolecules or high polymers or giant molecules are high-molecular-weight materials composed of repeating subunits called monomers. These materials may be organic, inorganic or organometallic and synthetic or natural in origin. Polymers are essential materials for almost every industry as adhesives, building materials, paper, cloths, fibers, coatings, plastics, ceramics, concretes, liquid crystals, photo resists coatings etc. They are also major components in plant and animal body. They are important in nutrition, engineering, biology, medicine, computers, space exploration, healthcare and the environment. The first synthetic polymer was produced in 1909; called Bakelite which could be moulded at a high temperature and it would retain its shape once cooled. But it wasn't until the World War I that significant changes took place in the polymer industry. Synthetic polymers have found wide spread application because of their low density, low cost and better performance.
The term nanocomposites means to distribute as much as possible amounts
of nanoparticles in a polymer matrix. It has been shown that, when using fiberreinforced
polymers, the maximum amount of fibers in the matrix is about 70 vol.%.
Actually, the fiber volume fraction in these materials varies between 20 and 60%.
Figure 1 summarizes the values to be achieved for various fillers used in composites.
In a volume element of 1 cm3, it was assumed that we have continuous fibers with
a diameter of 10 pm, particles (e.g., talcum) with a diameter of 1 pm, and nanotubes
with a diameter of 10 nm. The aspect ratios...