Polymers and Specific Functional Groups

A by-product!

Adding side groups to monomers changes some of their properties. These changes often occure in a graduated manner. So 1 in 10 gives a certain melting point, crystallinity, solubility if different solvents, clarity and so on. Changing to 2 in 10 gives different properties. Changing the length of the side chain gives you another group of properties.

With careful experimentation you can optimize the properties for your end use.

One typical use of this is the creation of flexographic ink binders for glossy magazines by the use of fatty acid modified monomers. wih careful experimentation you can get inks for plastic bread wrappers that stick well, are non toxice, opaque, will not rub off etc.

The same holds true for any other set of monomers to which assorted side chains can be attached to get tough and flexible polymers. Polyurethanes are well adapted to this to make waterprrof glues and soles for shoes.

You can even make polyurethane tires good for 500,000 miles. These are currently too costly for passenger car tires

You call then co-polymers, as opposed to homopolymers, which are comprised of only one type of monomer unit. The easiest way to incorporate a benzyl amine functionality into a styrene polymer is to have an olefin attached to your benzyl amine, such as in vinyl benzyl amine. Then you can copolymerize your benzyl amine monomer with styrene monomer in any ratio you want. You can do a solution polymerization in a suitable solvent, such as toluene, or a suspension polymerization, in which small particle beads of copolymer precipitate as formed, or as an emulsion polymer, in which small particles of polymer (200-400 nanometers) are stabilized by surfactant and suspended in water. These polymerizations are initiated by free radical sources such as azo compounds, peroxides or persulfates.

Co-polymers is the correct term as pointed out by WC.

2 ways to get end product-

1. Reacting monomers of styene and vinyl benzyl amine (also correct WC) say 10 moles to 1 for a 10:1 ratio, although varying reaction conditions (T, volume, etc) and monomer ratios, initiator, quencher, etc- you get different MWs and could be a solutionpolyer; emulsion (if surfactant used). initiator type depends on solvent you use, too. be careful with monomers, too, as their polymerization times vary, so you may need to gradually add the VBA, vs. one shot up front- check out polymerization reaction half lifes in Tanford or another polymer handbook.

2. Say you start (have to or want to) with polystyrene. React PS with nitric acid and sulfuric acid (orange brown liquid- use safe chem operating procedures) to nitrate the phenyl groups- product should go from milky white to a light yellow. Wash, and analyze for nitrogen- trial and error to get right conditions for say a 10:1 ratio. When teh right ratio is found, take the nitrated product and use a reducing agent to convert the nitro group to an amine group. Voila, you have your product. This process can be used also for surface modification of PS.