Abstract: Multi-armed, monofunctional, and hydrolytically stable polymers are described having the structure wherein Z is a moiety that can be activated for attachment to biologically active molecules such as proteins and wherein P and Q represent linkage fragments that join polymer arms polya and polyb, respectively, to central carbon atom, C, by hydrolytically stable linkages in the absence of aromatic rings in the linkage fragments. R typically is hydrogen or methyl, but can be a linkage fragment that includes another polymer arm. A specific example is an mPEG disubstituted lysine having the structure where mPEGa and mPEGb have the structure CH3O—(CH2CH2O)nCH2CH2— where n may be the same or different for polya- and polyb- and can be from 1 to about 1,150 to provide molecular weights of from about 100 to 100,000.

Abstract: Polymers of the monomer N-acryloylmorpholine having a single reactive moiety at one end of the polymer chain have the following structure: ##STR1## wherein --Z--X--Y is a polymer capping moiety, such as mercaptan, X represents a saturated residue of a linear or branched aliphatic series of the general structure --C.sub.r H.sub.2r -- in which r is an integer from 1 to about 12, Y is a reactive moiety and typically will be one of the reactive moieties commonly known in PEG chemistry, such as an --OH, --COOH, or --NH.sub.2 group, Z is a moiety that readily reacts to cap a polymer free radical, and n is an integer from about 6 to 280, which yields a number average molecular weight ("M.sub.n ") of from about 1,000 to 40,000. The monofunctional polymer is a suitable alternative to monofunctional PEG for modification of substances having biological and biotechnical applications.

Abstract: A water-soluble polyvinyl 5-membered lactam having a molecular weight ranging from about 1000 to about 20,000 and chain-terminated with a compound selected from the group consisting of compounds of the following formulas ##STR1## wherein R and R.sup.1 are C.sub.1 to C.sub.4 alkyl or substituted alkyl; n is 0 to 20; R.sup.II is ethylene; R.sup.III is C.sub.1 to C.sub.24 alkylene or substituted alkylene; and R.sup.IV is C.sub.1 to C.sub.4 alkyl or substituted alkyl; can be prepared by polymerizing an N-vinyl 5-membered lactam in a liquid solvent-chain terminator compound of the formula (I) or (II) in the presence of a free radical initiator. The lactam polymer so-obtained may be activated and grafted to (conjugated with) a drug or an enzyme to alter the properties thereof.

Abstract: Polymers of the monomer N-acryloylmorpholine having a single reactive moiety at one end of the polymer chain have the following structure: ##STR1## wherein -Z-X-Y is a polymer capping moiety, such as mercaptan, X represents a saturated residue of a linear or branched aliphatic series of the general structure --C.sub.r H.sub.2r -- in which r is an integer from 1 to about 12, Y is a reactive moiety and typically will be one of the reactive moieties commonly known in PEG chemistry, such as an --OH, --COOH, or --NH.sub.2 group, Z is a moiety that readily reacts to cap a polymer free radical, and n is an integer from about 6 to 280, which yields a number average molecular weight ("M.sub.n ") of from about 1,000 to 40,000. The monofunctional polymer is a suitable alternative to monofunctional PEG for modification of substances having biological and biotechnical applications.