as i expected dear, its the problem with your PDF reader not the document, i opened the document for you nothing abnormal, and i can see page 5 clearley, it do not contain much text , copied it for you below, Adobe acrobat reader is a weak program, try using Foxit or Nitro PDF readers.
the modiWed Ullmann coupling reaction. The num-
ber-average (Mn) and weight-average (Mw) molecu-
lar weights of the polymers 5–6 were determined by
GPC. The analysis demonstrated that the condensa-
tion yielded polymers of rather low molecular
weight with broad molecular weight distribution.
The GPC curve of oligomer 5 revealed Mn of
around 6200 with a polydispersity index of 3.1. The
molecular weight of polymer 6, which was synthe-
sized using dibromo monomer with the alkyl spacer,
was lower than that of 5. The value of Mn of the
polymer 6 was 2500 with polydispersity index of 1.6.
Carbazol-3-yl-based tetramer (9) was prepared