What is the repeat unit of design?

A layout in which the repeating unit appears directly on a horizontal line to the left or right of the original design unit. Also called block repeat, square repeat, and straight-across repeat.

Similarly one may ask, what is the meaning of Islamic art?

Islamic art encompasses the visual arts produced from the 7th century onward by people who lived within the territory that was inhabited by or ruled by culturally Islamic populations.

What are some of the characteristics of Islamic art?

A predominant characteristic of Islamic art is that it is nonrepresentational. Rather than representing images and figures as Western art does, Islamic art is comprised of geometric shapes and patterns. One of these is called the arabesque, which is an interweaving of floral, leaf and geometric designs.

What is an arabesque Islamic art?

The arabesque is a form of artistic decoration consisting of “surface decorations based on rhythmic linear patterns of scrolling and interlacing foliage, tendrils” or plain lines, often combined with other elements. Interlace and scroll decoration are terms used for most other types of similar patterns.

What kind of polymer is a Polyethene?

Condensation Polymers. Addition Polymers. Addition polymers such as polyethylene, polypropylene, poly(vinyl chloride), and polystyrene are linear or branched polymers with little or no cross-linking. As a result, they are thermoplastic materials, which flow easily when heated and can be molded into a variety of shapes.

Is Polyethene an alkane?

In terms of composition yes, but polyethylene cannot be compared to alkanes. Alkanes are molecules. Polyethylene is a polymer, made by combining hundreds of thousands of monomer molecules, in this case ethylene (CH2=CH2). An analogy is to compare bricks and buildings.

What do you mean by degree of polymerization?

The degree of polymerization, or DP, is the number of monomeric units in a macromolecule or polymer or oligomer molecule. an oligomer molecule, a block, or a chain. Some authors, however, define DP as the number of repeat units, where for copolymers the repeat unit may not be identical to the monomeric unit.

What is a condensation polymer?

Condensation polymers are any kind of polymers formed through a condensation reaction—where molecules join together—losing small molecules as byproducts such as water or methanol. The main alternative form of polymerization gives addition polymers, which derive from the conversion of alkenes to long-chain alkanes.

What is a cross linked polymer?

A cross-link is a bond that links one polymer chain to another. They can be covalent bonds or ionic bonds. “Polymer chains” can refer to synthetic polymers or natural polymers (such as proteins). Cross-linking is used in both synthetic polymer chemistry and in the biological sciences.

Why addition polymers are chemically inert?

Addition polymers are polyalkenes. The molecules are saturated, as all of the bonds holding the carbon chain together are single. This makes them generally unreactive and chemically inert. This means that condensation polymers are biodegradable and do not pose the same pollution hazard as addition polymers.

What is the molecular weight of PVC?

Crystalline density at 25oC: 1.52 g/cm3. Molecular weight of repeat unit: 62.50 g/mol.

Is ethene a monomer?

The smaller molecules are called monomers. Alkenes can act as monomers because they are unsaturated (they have a double bond): ethene can polymerise to form poly(ethene), also called polythene. propene can polymerise to form poly(propene), also called polypropylene.

Is Polyethene a plastic?

Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(ethylene)) is the most common plastic. The annual global production is around 80 million tonnes. Its primary use is in packaging (plastic bags, plastic films, geomembranes, containers including bottles, etc.).

What is the use of poly Chloroethene?

Uses of poly(chloroethene) (polyvinyl chloride) Poly(chloroethene) is used in building and construction, for example in making window and door profiles and in making pipes (from guttering to sewers, and ducting for cables). It is also much used for packaging, including film for food and bottles.

What are the different types of polymerization?

There are two basic types of polymerization, chain-reaction (or addition) and step-reaction (or condensation) polymerization. One of the most common types of polymer reactions is chain-reaction (addition) polymerization. This type of polymerization is a three step process involving two chemical entities.

How are polymers used in daily life?

Polymers are encountered in everyday life and are used for many purposes! Polymers are chains made of monomer subunits. For instance, poly(vinyl chloride) is a strong, corrosion-resistant polymer commonly used in plumbing applications, whereas polyethylene is an example of a flexible polymer found in plastic bags.

Which common material is an example of a polymer?

Common examples. Polymers are of two types: naturally occurring and synthetic or man made. Natural polymeric materials such as shellac, amber, wool, silk and natural rubber have been used for centuries. A variety of other natural polymers exist, such as cellulose, which is the main constituent of wood and paper.

How a polymer is made?

Synthetic polymers are produced by chemical reactions, termed “polymerizations.” Assorted combinations of heat, pressure and catalysis alter the chemical bonds that hold monomers together, causing them to bond with one another. Most often, they do so in a linear fashion, creating chains of monomers called polymers.

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