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Home » Class 11 » Chemistry » p-Block Elements » Silicones

Silicones

Last Updated on July 3, 2023 By Mrs Shilpi Nagpal

Silicones are synthetic organosilicon polymers containing repeated R2SiO units held by Si-O-Si linkages.

These compounds have general formula (R2SiO)n where R=methyl or aryl group.

Preparation

When methyl chloride reacts with silicon in the presence of copper as a catalyst at 570 K , various types of methyl substituted chlorosilanes of formula CH3SiCl3 , (CH3)2SiCl2, (CH3)3SiCl along with small amount of (CH3)4Si are formed.

Hydrolysis of dichlorodimethylsilanes followed by polymerization yields chain polymers.

structure of silicone

Properties

1) Silicones made up of short chain molecules are oily liquid, silicones with medium chains behave as viscous oils, jellies and greases, those with very long chains behave as rubbery elastomers and resins.

2) They are chemically inert i.e. resistant to oxidation , thermal decomposition or to attack by organic reagents.

3) Silicones being surrounded by non-polar alkyl group are water repelling in nature.

4) They are heat resistant and have high dielectric strength i.e. have good electrical insulating properties.

Uses

1) For making water proof papers , wool , textile , wood by coating them with a thin film of silicone.

2) As sealants and electrical insulators.

3) As lubricant at high as well as low temperature since there is little change in their viscosities with temperature.

4) Being biocompatible, they are used in surgical and cosmetic implants.

Filed Under: Chemistry, Class 11, p-Block Elements Tagged With: general formula of silicones, preparation of silicones, properties of silicones, silicones, uses of silicones

About Mrs Shilpi Nagpal

Author of this website, Mrs. Shilpi Nagpal is MSc (Hons, Chemistry) and BSc (Hons, Chemistry) from Delhi University, B.Ed. (I. P. University) and has many years of experience in teaching. She has started this educational website with the mindset of spreading free education to everyone.

Reader Interactions

Comments

  1. Ayush Nath says

    January 24, 2018 at 12:23 am

    It really helped me. Thanks plz keep up the gud work
    .

  2. Mrs Shilpi Nagpal says

    January 24, 2018 at 10:39 am

    Thanks Ayush.

  3. Siddharth says

    February 23, 2019 at 7:36 pm

    Thanks mam for giving us(students) these notes…

  4. Amrita says

    March 17, 2019 at 9:02 am

    Wo this is really helfful for me plz always make this types of notes

  5. Bijoy JHa says

    January 9, 2020 at 12:26 pm

    Your work madam is highly appreciated. Keep it up please.

  6. Swarangi gaikwad says

    January 12, 2020 at 9:08 pm

    It’s really helpful

  7. Anurooop says

    January 30, 2020 at 3:25 pm

    These notes are like guide to understand ncert . These are not different than ncert but are in a easy way to help cover every line and each n every word of ncert . Thanks a lot mam

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