What are Phosphazenes give an example?
Another class of compounds called phosphazenes are represented with the formula (−N=P(−X) 2−) n, where X = halogen, alkoxy group, amide and other organyl groups. One example is hexachlorocyclotriphosphazene (−N=P(−Cl) 2−) 3.
What are Polyphosphazene used for?
Poly[(organo)phosphazenes] are a unique class of extremely versatile polymers with a range of applications including tissue engineering and drug delivery, as hydrogels, shape memory polymers and as stimuli responsive materials.
How are Phosphazene prepared?
The poly(dichlorophosphazene) (PZ) was obtained by melt ring-opening polymerization of hexachlorocyclotriphosphazene (HCCP) under vacuum at 250°C for 3 h. After this time, the polymer was dissolved at room temperature in anhydrous THF, and it was separated by precipitation into n-heptane.
What is polymeric backbone in Phosphazene?
Polyphosphazenes (PPHOSs) are polymers with an inorganic backbone consisting of alternating phosphorus and nitrogen atoms, separated by alternating single and double bonds, and organic substituents (R) covalently bonded to the phosphorus atoms as side groups (see Scheme 1.44).
What are silicones and Phosphazenes?
SILICONES AND PHOSPHAZENES. groups may be attached to a skeletal atom. This will affect the flexibility of polymers, their ability to react with chemical reagents and interactions with other polymers. are two important class of polymers with high commercial potential.
What are Phosphonitrilic polymers?
Such phosphonitrilic halide polymers of high molecular weight are generally linear in structure and are observed to possess elastomeric properties and hence are often termed inorganic rubbers.
How do you make polysiloxane?
Linear polysiloxane can be synthesized by both anionic and cationic polymerizations of cyclic siloxanes such as hexamethylcyclotrisiloxane (n = 3) and octamethyl cyclotetrasiloxane (n = 4). Anionic polymerization is initiated by hydroxide, alkoxides, phenolates, silanolates and siloxoanolates.
How many types of inorganic polymers are there?
This article discusses the major classes of inorganic polymers, including borates and three classes of silicon polymers—silicates, silicones, and silanes.
What is Polyphosphazene and give its preparation?
Polyphosphazenes are macromolecules with a phosphorus– nitrogen backbone, substituted by two (commonly organic) side. groups on the phosphorus atoms to give poly(organo)phosphazenes. (Fig. 1).
What are the properties of phosphazene?
IV. C Structural/Mechanical Properties
|Properties||Nylon 6||Nylon 6–clay nanocomposites|
|Charpy impact strength (KJ/m2)||6.21||6.06|
|Heat distortion temperature 1.82 MPa (°C)||65||152|
|Coefficient thermal expansion (x, y)||6.3 × 10−5||13 × 10−5|
|Water absorption (%)||0.87||0.51|
How is silicone resin made?
Silicone resins are prepared by hydrolytic condensation of various silicone precursors. In early processes of preparation of silicone resins sodium silicate and various chlorosilanes were used as starting materials.
Why is silicone rubber flexible?
Advantages of silicone rubber
Silicone’s thermal stability means it retains its structure and properties over a wide temperature range. This extends to low temperatures too, which means this synthetic rubber can maintain its flexibility even at -100°C.
What are different types of silicones?
Silicones take many forms, the basic ones of which are fluids, emulsions, elastomers and resins.
How are silicones manufactured?
This is done by heating a large volume of quartz sand to temperatures as high as 1800˚C. The result is pure, isolated silicon, which is allowed to cool and then ground into a fine powder. To make silicone, this fine silicon powder is combined with methyl chloride and heated once again.
What are Phosphonitrilic compounds examples?
Phosphonitrilic chloride tri~ner, tetramer, and polymer have been studied by X-ray and electron diffraction (23-28). The trimer exists as an almost planar six- membered ring, the tetramer as a puckered eight-membered ring, and the polymer as a linear chain which is arranged in the form of a helix.
Which polymer is used for PVDC?
polyvinylidene chloride (PVDC), a synthetic resin produced by the polymerization of vinylidene chloride. It is used principally in clear, flexible, and impermeable plastic food wrap.
What is polysiloxane made of?
Polysiloxanes, or silicones, are a general category of polymers consisting of a silicon-oxygen backbone with organic groups, typically methyl groups, attached to the silicon atoms (Colas and Curtis, 2004). Certain organic side groups can be used to link two or more chains together.
What is difference between polysiloxane and silicon?
Silicone is a synthetic polymer, and there are many kinds of silicones also known as polysiloxanes. A siloxane comprises silicon atoms and alternating oxygen, whereas polysiloxanes are polymers of inert compounds composed of multiple siloxanes.
What is largest inorganic polymer?
Polyphosphazenes. Polyphosphazenes are by far the largest class of inorganic polymers. Hundreds of different polymers of this type have been synthesized, with a range of physical and chemical properties that rival those of organic polymers.
Is silicone inorganic polymer?
A silicone polymer also known as polysiloxane is a type of polymer (inorganic polymer) that is mainly made up of polymerized siloxane (−R2Si−O−SiR2−). They are basically a type of synthetic polymer and are usually made up monomers that are bonded in long chains.
How is NPCl2 3 Prepared?
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. Hexachlorophosphazene together with the related (NPCl2)4 are precursors to inorganic polymers called polyphosphazenes.
What is phosphazene structure?
H Phosphazenes. Phosphazenes contain the basic structure unit –X2P. N–. Although some monomeric forms are known, most are obtained initially as six- or eight-membered rings. The rings consist formally of alternating double and single bonds, but the uniform dimensions of the rings indicate delocalization.
What is silicone chemical formula?
The general formula of silicone is (R2SiO)x, where R belongs to any one of the organic groups. Poly-dimethylsiloxane is the most silicone compound can which illustrates the primary characteristics of the organic class.
What are the two types of silicone?
The two liquid silicone rubber types include food grade and medical grade.
What is the difference between silicone and epoxy?
Silicones are resistant to high temperatures and chemicals. They typically have lower Tg and modulus than epoxies and lower adhesion strength than both epoxy and polyurethane adhesives, often requiring primers.