Effects of maintaining temperature (T3) and time (t) on properties and structures of product poly(dimethyldiallylammonium chloride) (PDMDAAC) are researched in this article. The results showed that higher the T3 shorter the time t needed for polymer products' intrinsic viscosity ([?]) and monomer conversion (Conv.) to reach their maximum values. The maximum [?] was 4.69 dL g-1 and corresponding Conv. was 100.00%, when t = 96 h and T3 = 55 degrees C. The reaction phenomena and products' FTIR and NMR spectra indicated the possible reasons for the increase of [?], the formation of branched and crosslinked products after the conversion was more than 100.00% in T3 term were the results of polymerization happened among the residual monomers, hanging and terminal double bonds. Compared with solubility of products, it was found that the time needed for dissolving the linear, branched, and crosslinked PDMDAAC products increased in turn, whereas their dissolved amount decreased reversely. The linear product's Mw, Mw/Mn, and Rg measured by GPC-MALLS were 4.169 x 106, 5.109, and 127.7 nm, respectively. Meanwhile, the linear and crosslinked products were characterized by DTA-TG. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012