Table 2.

Dimensional characteristics of powders obtained from the PVP-HA composites (samples 1–3, Table 1) after heat treatment at T = 400 °C, determined by TEM, BET and XRD methods.

Sample	Polymer Concentration in PVP *-HA * Mixture, wt %	PVP/HA Ratio, wt %	Specific Surface Area (BET) *, m2/g	CSR *, nm	Particles Size from TEM Data, nm
1	2.76	0.028	16.7	17.7	30
2	5.52	0.014	19	19.6	33
3	11.00	0.07	37	17.9	45
HA	0	-	18	31.7	35

* PVP—polyvinylpyrrolidone; HA—hydroxyapatite; BET—Brunauer–Emmett–Teller specific surface area method; CSR—coherent scattering region.