Poly(dichlorophosphazene)
Encyclopedia
poly, also called dichlorophosphazine polymer or phosphonitrilechloride polymer, is chemical compound
with formula (-PNCl2-)n. It is an inorganic
(hence carbon
-free) polymer
, whose backbone is a chain of alternating phosphorus
and nitrogen
atoms, connected by alternating single and double covalent bond
s.
The compound can be prepared by polymerization of hexachlorophosphazene
((PNCl2)3) by heating to ca. 250 °C. It is an "inorganic rubber" and the starting material for many other polymers with the -P=N- backbone (polyphosphazene
s), which have important commercial uses.
at Pennsylvania State University
synthesized a souble form of the polymer, which opened the doors to the development of many derivatives.
and benzene
, wherein it can be derivatized by replacement of the chlorine atoms with -OR or -NR2 groups (R = alkyl, aryl
) to yield many other polyphosphazenes. Some of these organically modified polymers are hydrolytically stable and exhibit some attractive properties such as low glass transition temperatures.
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
with formula (-PNCl2-)n. It is an inorganic
Inorganic compound
Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...
(hence carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
-free) polymer
Polymer
A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...
, whose backbone is a chain of alternating phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...
and nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
atoms, connected by alternating single and double covalent bond
Covalent bond
A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding....
s.
The compound can be prepared by polymerization of hexachlorophosphazene
Hexachlorophosphazene
Hexachlorophosphazene is an inorganic compound with the formula 3. The molecule has a cyclic backbone consisting of alternating phosphorus and nitrogen atoms. It can be viewed as a trimer of the hypothetical compound N≡PCl2...
((PNCl2)3) by heating to ca. 250 °C. It is an "inorganic rubber" and the starting material for many other polymers with the -P=N- backbone (polyphosphazene
Polyphosphazene
Polyphosphazenes are a class of inorganic polymers with the repeat unit . The substituents R,R' are usually alkoxy, amino, , or halogens ....
s), which have important commercial uses.
History
Poly(dichlorophosphazene) was discovered by H. N. Stokes in the 19th century, and at that time its superior properties over natural rubber were already noted. In 1965, Harry R. AllcockHarry R. Allcock
Harry R. Allcock is Evan Pugh Professor of chemistry at Pennsylvania State University.Harry Allcock obtained his B.S. in 1953 and his Ph.D. in 1956, both at the University of London. He is notable for his work on the "inorganic rubbers" with a phosphorus-nitrogen backbone . With James E...
at Pennsylvania State University
Pennsylvania State University
The Pennsylvania State University, commonly referred to as Penn State or PSU, is a public research university with campuses and facilities throughout the state of Pennsylvania, United States. Founded in 1855, the university has a threefold mission of teaching, research, and public service...
synthesized a souble form of the polymer, which opened the doors to the development of many derivatives.
Uses
Poly(dychlorophosphazene) is not water-resistant. However, it is soluble in organic solvents such as THFThF
Follicular B helper T cells , are antigen-experienced CD4+ T cells found in the B cell follicles of secondary lymphoid organs such as lymph nodes, spleens and Peyer's patches, and are identified by their constitutive expression of the B cell follicle homing receptor CXCR5...
and benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
, wherein it can be derivatized by replacement of the chlorine atoms with -OR or -NR2 groups (R = alkyl, aryl
Aryl
In the context of organic molecules, aryl refers to any functional group or substituent derived from an aromatic ring, be it phenyl, naphthyl, thienyl, indolyl, etc....
) to yield many other polyphosphazenes. Some of these organically modified polymers are hydrolytically stable and exhibit some attractive properties such as low glass transition temperatures.