Matter & Energy


Matter is composed of atoms or groups of atoms called molecules. The arrangement of particles in a material depends on the physical state of the substance. In a solid, particles form a compact structure that resists flow. Particles in a liquid have more energy than those in a solid. They can flow past one another, but they remain close. Particles in a gas have the most energy. They move rapidly and are separated from one another by relatively large distances.

Vegetable Fibers

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Vegetable fibers are predominantly cellulose, which, unlike the protein of animal fibers, resists alkalies. Vegetable fibers resist most organic acids but are destroyed by strong mineral acids. Improper use of most bleaches can also weaken or destroy these fibers.

There are four major types of vegetable fibers: seed fibers, which are the soft hairs that surround the seeds of certain plants; bast fibers, the tough fibers that grow between the bark and stem of many dicotyledonous plants (see Dicots); vascular fibers, the tough fibers found in the leaves and stems of monocotyledons (see Monocots); and grass-stem fibers. Other fiber types, of limited utility, include strips of leaf skins, such as raffia; the fiber of fruit cases, such as coir; and palm fibers.

Only two seed fibers, cotton and kapok (see Ceiba), have commercial importance. Cotton fiber, which grows in the seed pod of cotton plants, is the only one that is useful for the manufacture of textiles. Different species of cotton plants produce fibers of different lengths. Long-staple fibers are spun into fine, strong yarns, which are then woven into better-quality fabrics. Short-staple fibers produce coarser yarns for durable fabrics. Cotton yarns can be dyed (see Dyeing) and printed easily, so that they are useful for producing woven fabrics with a multitude of colors and designs. Kapok cannot be spun but is used as upholstery stuffing. Because it is hollow, kapok is buoyant. It was once used in flotation devices such as life preservers, but it has largely been replaced by other materials.

A wide variety of bast fibers are used in applications ranging from fine woven textiles to cordage. Linen cloth is made from flax. Coarser clothes and rope are produced from hemp, jute, ramie, and sunn.

Vascular fibers are used almost exclusively for making cordage. They include agave (sisal), henequen, manila hemp, and yucca. The vascular fibers of pineapple have been used in the production of textiles. Entire stems of some grasses and straws, such as esparto, are woven as fibers for hats and matting.