M'^ 1 *»
1. To build a flexible, high-moteeuiar-weight polymer
-jr.
Polyoxyalkylene group represented by
ΐ;#
-—_—__
2M TO prepare filament* with a variety of fiber properties Slock Polymer " A "
Block Polymer " B '
Block Copolymer X « bli-Urothane linkage 3. To croit link polymers having hydrojyl or other activehydrogen groups
Polyvinyl Alcohol
Second NCO available for crosslinking. 4. To block undesirable polymer end groups or side chains.
Γ y* - ^\
Jr~° Cellulose Triacetate
1 H-NCO Ο Corb. CH20 Ca,
CM^O Carb.
Ο Crb.
Cellulose Tricarbamate
-.^
W
K*
A^i
S. To impart non-adhering properties
>·«ΐ Polyvinyl Alcohol Film. Good adhesten due to polar O H groups.
c *ο NH
C!SMÏ8
isocyaiiates
Non-adhering surface due to loss of polar O H group. The hydrocarbon CiaH38 has paraffin character, making adhesion difficult Tendency to crystallize reduced due to bulk of R group, keeping chains apart, and reducing symmetry of polymer molecule. 6. To add biologic ally-active groups NCQ4-A. NHS
» Cl^T
Λ - N H C Nl
Biologically Active Urea Derivative
"Mother Lode" for New Product Prospectors The polyisocyanates are universal "building block" chemicals used to bond together other chemical structures to produce products with built-in, pre-determined char acteristics. For example, flexible resins such as polyether glycols may be joined with a polyisocyanate to build a flexible, high-molecular-weight polymer (1). Or, by simply replac ing the polyether with a polyester resin, a more rigid product results. Certain block polymers may be joined to each other with isocyanates to prepare filaments with a variety of fiber properties (2). Using diisocyanates to crosslink polymers having hy droxy! or other active-hydrogen groups increases modulus, melting point, temperature and solvent resistance in the end product (3). Reduced sensitivity to water swelling and shrinkage in materials such as wool may also be realized. The mono-isocyanates may be used to block undesir able polymer end groups or side chains. The substitution of a urethane group for a hydroxyl influences the hydrophilic character of the polymer, its solubility and degree Circle No. 135 on Readers' Service Card
of hydrogen bonding that takes place. Isocyanate modi fication of cellulose, for example, gives results similar to the conversion to cellulose acetate (4). Mono-isocyanates can also be used to add hydrophobic groups, to impart non-adhering properties, to reduce crys tallization tendencies of polymers (5) and to add bio logically-active groups (6). Mobay manufactures a broad range of mono-func tional and poly-functional isocyanates of both the aro matic and aliphatic type. If you would like to explore further the prolific possibilities of this new frontier of product creation with us, a brief letter stating your field of interest will receive prompt attention. MOBAY CHEMICAL COMPANY Dept. AC-1, Penn-lincoln Parkway West Pittsburgh 5, Pa.
Mobay manufactures isocyanates, polycarbonates and urethane chemicals for foams, elastomers and coatings.
First tn Urethane Chemistry
