Yaa Nylon: The Outset Synthetic Fiber

Nylon: The First Synthetic Fiber

Anik Yusuf
Department of Textile Engineering
Ahsanullah University of Science & Technology, Dhaka
Email: anik.yusuf@gmail.com

Introduction:
Polyamides are polymers that comprise an amide grouping (-CONH-) inward it's backbone every bit a recurring locomote of the chain. They are oft referred to every bit Nylon which has thermoplastic silky properties.

Nylon :
When less than 85% of amide linkage are attached straight to 2 aliphatic groups the polyamides are known every bit Nylon.

Nylon fiber

Invention :
Nylon was the start commercially successful synthetic polymer. Wallace Carothers is credited amongst the innovation of synthetic security together with nylon closed to 1933 at DuPont. It was start produced on Feb 28, 1935 at the DuPont Experimental Station. Fiber went commercial closed to 1938 together with is even so used extensively today. DuPont recouped all investment inward Nylon 6,6within thirty days of establish startup every bit at that spot had been goose egg similar it earlier !!!

Nomenclature:
Nylons are formed mainly yesteryear condensation polymerization though they tin too live formed yesteryear add-on polymerization .

It tin live formed yesteryear three approaches –

Nylon 6,6 :
It’s made from Adipic acid together with Hexamethylene diamine . Both of these monomers comprise half-dozen carbon atoms therefore the refer Nylon 6,6 . Before the refer Nylon 6,6 was used , it was called yesteryear a codename “fiber 66”

Nylon 6:
In 1938 Paul Schlack of the IG Farben Company inward Deutschland polymerized Caprolactum& created a unlike cast of the polymer identified every bit Nylon 6. It’s a homopolymer which is formed yesteryear band opening polymerisation.

***The Degree of Polymerisaton for Nylon half-dozen & Nylon 6,6 ranges betwixt 100 to 180 & their Average Molecular Weight ranges betwixt 15,000 to 30,000

Spinning Process Diagram:

Spinning procedure of nylon

Chemical Properties of Nylon:

(1) Swelling of Nylon:
The Oxygen of the Carbonyl grouping is slightly negative & the hydrogen (imino hydrogen) is slightly of positive charge.The polar grouping inward Nylon together with is responsible for swelling inward H2O or inward polar solvents or inward dyeing amongst disperse & metallized dyes.

(2) Melting of Nylon:
Melting betoken increases because of the next 2 reasons –

(a)The increment of CONH grouping to CH2 groups:
The amide grouping is planar inward nature because of the partial double bond grapheme of C-N bond. It has been estimated that the barrier for rotation nearly this bond may live 63 Kj/mol (15 Kcal/mol) or higher.For this argue if the ratio of CONH grouping to CH2 is high than melting temperature would live high also.

(b) Hydrogen Bond:
The polar polyamide grouping is responsible for hydrogen bonding betwixt polyamide chains. Whether the no. of CH2 groups betwixt CONH is strange or fifty-fifty is a rattling of import factor.

Figure : Schematic of a Hydrogen bonded sail of PA half-dozen amongst antiparallel (A) & Parallel (B) orientation of amide group.

If the no. of CH2 grouping betwixt amide groups is strange & the orientation of the chain is anti-parallel/opposed (Fig. A) than it allows consummate hydrogen bonding.But if the orientation of the chains are parallel/same the bonding is non complete.

Now the changing from a parallel array to anti-parallel array requires the inverting of the whole chain inward illustration of strange no. but alone a segmental lateral motility is needed if the no. of CH2 grouping is fifty-fifty (Ex. Nylon 6,6).

So the Nylon half-dozen polymer has lower melting betoken than Nylon 6,6

***Based on this nosotros tin tell that the polyamide having strange no. of CH2 grouping volition convey lower melting temperature that the similar form of polyamide having a fifty-fifty no. of CH2 group***

(c) Introduction of Side Chains:
If side chains are introduced into the carbon skeleton so it interferes amongst the intermolecular forces betwixt the amide groups.It results inward reduction of melting betoken together with increases solubility inward organic solvents.

(d) Introduction of Aromatic Ring:
when the amide grouping is connected to aromatic rings it results inward chain stiffening together with higher melting temperature. This cast of polyamides are called aramids which ordinarily degrades without melting so it can’t live melt spun.

References:

1. Apparel Fibers – MD Engr. Md. Nazirul Islam
2. Industrial Polymers Handbook –Edward S. Wilks
3. Man Made Fibres –CesareAndreoli&FabrizioFreti

Images:

1. http://en.wikipedia.org/wiki/Nylon
2. http://d2n4wb9orp1vta.cloudfront.net/resources/images/cdn/cms/0712ptKHmaterials3.jpg
3. http://www.pslc.ws/macrog/protein.htm
4. http://guweb2.gonzaga.edu/faculty/cronk/biochem/P-index.cfm?definition=peptide_bond
5. http://www.plasticsacademy.org/swp/articles.php?articleId=39

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