Developed by: Marjan Polymer Industries. Pakistan
Project In-charge: Dr. Muhammad Abid
Collaborators: Prof. Dr. Tahir Jamil (late), Prof Dr. Khan, Dr. Nafisa
Year: 2014
Polyurethanes belongs to class of alternating segmented polymers which comprises mainly two alternative segments such as soft and hard segments. The Polyurethane dispersions were made by dispersing amphiphilic pre-polymers using soft segment (polyol), hard segment (diisocyanates), and internal emulsifier followed by chain extension steps.
Adopted Synthesis Process
The pre-polymer process. This technique is used to produce polyurethane coatings, elastomers and sealants.
2 OCN–R–NCO + HO ~~~~~~~~~ OH
(Oligo-diol)
OCN–R–NHCOO ~~~~~~~~~~ OCONH–R–NCO
(Pre-polymer)
This pre-polymer having free NCO terminals which further reacts with chain extenders and the resulting polymer (polyurethane) formed is a high molecular weight polyurethane.
OCONHRNHCOO ~~~~~~~~~~~~OCONHRNCO + HO–R1–OH
(Pre-polymer) (Diol)
O–R1–O [CONHRNHCOO ~~~~~~~~~~~ OCONHRNHCOO–R1–O]n
(Polyurethane)
Results:
- Transparent Coating
- High Hardness
- Excellent UV Protection
- Excellent Impact Resistance
- Excellent Chemical Resistance
- High Gloss
- Good Scratch Resistance
- Good Rheological Flow
- Excellent Colloidal Stability
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