PA Type (Aminopropyl PEG)

2arm branched PEG, -(CH2)3-NH2, Mw 20,000   
2arm branched PEG, -(CH2)3-NH2, Mw 40,000
2arm branched PEG, -(CH2)3-NH2, Mw 60,000
2arm branched PEG, -(CH2)3-NH2, Mw 80,000