longer chains with fewer branches have _________ intermolecular forces
stronger
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stronger intermolecular forces between polymer chaisn causes the polymers to be ....
stronger and more rigid
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why are VdW stronger in polymers with few/no branches?
polymer chains can pack more closely together
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why is poly(phenylethene) i.e polystyrene more flexible than poly(ethene)
benzene ring ocming off main carbon chain is a large branch, which makes it difficult for the chains to pack closely together so they can only form weak VdW
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polychloroethene (PVC) is... (properties)
hard and brittle
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why is PVC hard and brittle
contains Cl causing delta + charge on carbon atoms and delta - on Cl, this createss permanent dipole-dipole forces between the polymer chains (making PVC hard but brittle)
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uses of PVC
drain pipes/window frames
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what does a plasticiser do
makes a polymer more flexible
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how does a plasticiser work
the plasticiser molecules get between the polymer chains and push them apart, reducing strength of IMF betweeen the chains so the chains can slide around more, making them flexible
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