Primary and Secondary Plasticizers

Mutual miscibility between plasticizers and polymers is an important criterion from a practical point of view. If a polymer is soluble in a plasticizer at a high concentration of the polymer, the plasticizer is said to be a primary plasticizer. When the polymer solubility is limited in the technologically important high concentration range, the plasticizer is called a secondary plasticizer. In this case, two phases are present after the plasticization process one phase where the polymer is only slightly plasticized and one phase where it is completely 

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Primary and secondary plasticizers can be distinguished. Primary plasticizers are compatible with the polymer, while secondary plasticizers are less compatible... 

Plasticizers should be relatively nonvolatile, nonmobile, inert, inexpensive, nontoxic, and compatible with the system to be plasticized. They can be divided based on their solvating power and compatibility. Primary plasticizers are used as either the sole plasticizer or the major plasticizer with the effect of being compatible with some solvating nature. Secondary plasticizers are materials that are generally blended with a primary plasticizer to improve some performance such as flame or mildew resistance, or to reduce cost. The division between primary and secondary plasticizers is at times arbitrary. Here we will deal with primary plasticizers. 

A distinction is also made between primary and secondary plasticizers. Primary plasticizers interact directly with the polymer chains, whereas secondary plasticizers are actually only diluents for the primary plasticizers. For this reason, secondary plasticizers are also called extenders. Thus, depending on the polymers, a given plasticizer can act as either a primary or a secondary plasticizer. For example, heavy oils are extenders for PVC, but primary plasticizers for elastomers. 

Because of its unique combination of properties PVC is never handled on its own. Instead a complex formulation incorporating several additives is used. A typical base formulation contains PVC resin, heat stabilizer(s), internal lubri-cant(s), external lubricant(s), processing aid, and additionally, impact modifier, filler(s), pigment, UV stabilizer, as well as primary and secondary plasticizers (see Heat Stabilizers Plasticizers UV Stabilizers). 

AH the common monobasic (107) and dibasic esters (108) of tetrahydrofurfuryl alcohol have been prepared by conventional techniques the dibasic esters and some of the mono esters are effective as primary or secondary plasticizers for vinyl polymers. Tetrahydrofurfuryl acrylate [2399-48-6] and methacrjiate [2455-24-5] specialty monomers, have been produced by carbonylation (nickel carbonyl and acetylene) of the alcohol (109) as weU as by direct esterification (110—112) and ester interchange (111). 

During 1944 at U.S. Air Force, Wright-Patterson AFB, Dayton, OH the first successful all plastic airplane (primary and secondary structures) was designed, fabricated, and flight tested (Fig. 4-11). It used... 

Primary and secondary nitroalkanes, and substrates containing terminal em-dinitroaliphatic functionality, have one or more acidic a-protons, a consequence of inductive and resonance effects imposed by the nitro group. As a result, such compounds can behave like carbanions and participate in a number of addition and condensation reactions which are typical of substrates like ketones, aldehydes, and /S-ketoesters. Such reactions are extremely useful for the synthesis of functionalized polynitroaliphatic compounds which find potential use as explosives, energetic oligomers and plasticizers. 

R.J- Buxton T-M- Massis, Compatibility of Explosives with Structural Materials of Interest , Sandia Laboratories", Aug 1970 June 1972 reviewed by G. Cohn, Edit, in Expls Pyrots 6(2), 1973 (Intended as an aid to the design engineer, the reports list 1500 structural material combinations and label them as compatible, incompatible, or marginal. The structural materials include metals, plastics and adhesives, while the expls include primary and secondary expls, propellants and pyrotechnics)... 

When using plastic trays, the primary and secondary antibody solution volume should be increased to 25 to 50 ml. For membrane strips, incubation trays with individual slots are recommended. Typically, 0.5 to 1 ml solution/slot is needed. 

The examination includes basic equipment process and program control prevention and corrective action on primary and secondary equipment, delivery of plastic materials, material handling, storage, quality assurance machinery and plant safety handling tools and equipment, packaging fabricated products, and general knowledge of plastics. 

Scum. It consists of the floatable materials skimmed from the surface of primary and secondary settling tanks. Scum may contain grease, oils, fats, waxes, soaps, hair, paper, cotton, and plastic materials that have specific gravity less than 1. 

Filled polymers play a role in primary and secondary protection against y-radiation. The photons interact with matter by photoelectric absorption and Rayleigh scattering. For primary partitions which separate an unshielded source from its surroundings, lead bricks or concrete blocks are used. For the secondary partitions which protect personnel from radiation, a protective shield or vest can be made by incorporating metal particles or lead oxide in rubber or plastic. Such shields are used by physicians and dentists or their patients to limit exposure to x-rays. The radiation... 

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