Table 4. Means and standard deviations of elastic modulus of the control and copolymer groups/GPa.

Test groups	Acrylic resins
	QC-20	Acron MC
Control (100% PMMA)	2.07±0.07	2.07±0.19
5% copolymer (5% AAm+95% PMMA)	2.37±0.13	2.40±0.27
10% copolymer (10% AAm+90% PMMA)	2.99±0.08*	2.91±0.29*
15% copolymer (15% AAm+85% PMMA)	3.59±0.21*	3.55±0.18*
20% copolymer (20% AAm+80% PMMA)	3.30±0.14*	2.86±0.20*

AAm, acrylamide monomer; PMMA, poly(methyl methacrylate).

*Symbol indicates significant differences between control and copolymer groups in each column (P<0.01).