A new strategy was developed for preparation of high fluidfy nylon 6 on a large scale.Generation 1

2

3 (G1

G2

G3) polyamidoamine (PAMAM) dendrimers reacted with p-phthalic acid by equimolar terminal groups in water solutions

respectively，and mother salt solutions were then prepared.The high fluidity nylon 6 was prepared with suitable quantity of mother salt solution

end capping agent (acetic acid) and ε-caprolactam by in situ polymerization.By changing the quantity of mother salt solution or the generation of PAMAM dendrimers

different samples of high fluidity nylon 6 were obtained.Blue shifts were found for the peaks of NH (γN—H and 2δN—H ) of the high fluidity nylon 6 compared with pure nylon 6 in the IR spectra.Compared with pure nylon 6

the samples of high fluidity nylon 6 with low content of PAMAM units (0.3 wt%～0.5 wt%) had greater MFI

the value of MFI was improved about 70%～90%.It was also found that there was a drastic increment in MFI when the content of PAMAM units in PA6 matrix increased from 0.5 wt% to 1.2 wt%

while the molecular weight of the high fluidity nylon 6 did not decrease.For the high fluidity nylon 6 with low content of PAMAM units (0.3 wt%～0.5 wt%)

the tensile strength did not decrease while the elongation at break decreaed (ca.20％～35%)， and the izod impact strength of different kinds of high fluidity nylon 6 increased.DSC thermograms of nonisothermal crystallization exhibited that the peak temperature of high fluidity nylon 6 was lower than that of pure nylon 6

and the peak of crystallization curve broadened comparing with the pure nylon 6 at the same crystallization condition

which broadened more with increasing the generation or the content of PAMAM units.Broader peak means the crystallization rate was decreased and the fluidity was improved

which benefits molding of small parts with thin walls or precision parts.