Pulverisette 6 classic line

The inorganic precursor powder and liquid components of the SrCPC cement were prepared according to a previous work (Sprio et al., 2016 (link)). Briefly, a Sr-doped α-tricalcium phosphate solid precursor (Sr-αTCP) was prepared by mixing calcium carbonate (CaCO₃, Sigma Aldrich, St. Louis, MO, United States), dicalcium phosphate dibasic anhydrous (CaHPO₄, Sigma Aldrich) and strontium carbonate (SrCO₃, Sigma Aldrich), followed by thermal treatment at 1400°C for 1 h and rapid cooling, to obtain a final composition of Sr/(Ca + Sr) ≈ 2 mol% (hereinafter coded as SrCPC). Such a powder was milled by planetary mono mill (Pulverisette 6 classic line, Fritsch, Germany) for 50 min at 400 rpm using a zirconia jar with 5 mm diameter grinding media. The liquid component of the paste was made of aqueous solutions of disodium hydrogen phosphate dihydrate, 5 wt% (Na₂HPO₄∙2H₂O, Fluka) and sodium alginate, 2 wt% (Alginic Acid Sodium Salt from Brown Algae, Sigma Aldrich). Finally, appropriate amounts of powder and liquid, according to liquid-to-powder (LP) ratio equal to 0.6, were mixed to obtain the SrCPC cements.

In order to combine magnesium hydroxide and lignin, the process of mechanical grinding of pure precursors with their simultaneous mixing was employed using a Pulverisette 6 Classic Line planetary ball mill (Fritsch, Idar-Oberstein, Germany). The vessel with the materials subjected to homogenization (Mg(OH)₂:lignin mass ratio equal to 1:1) was placed eccentrically on the rotary base of the planetary ball mill. The base rotation direction was opposite to the vessel rotation direction, with a speed ratio of 1:−2. The movement of agate balls within the vessel is the result of the action of the Coriolis force. The speed difference between the balls and the vessel results in the interaction of friction and impact forces, which generate high dynamic energy. The interaction of these two phenomena leads to a very high degree of size reduction of the ground/homogenized material. The mill operated with a change in rotation occurring every 5 min. To achieve the appropriate homogeneity of the final material, the grinding process was continued for 2 h. To prevent a possible overheating of the material due to continuous grinding, the mill automatically shut down every 30 min for 5 min, after which it resumed operation. Upon appropriate grinding, the hybrid material was separated through a 40 μm-mesh sieve.

The well-cleaned and sun-dried cassava bagasse obtained from a cassava starch industry based in Thailand was supplied by the Excellent Centre of Waste Utilisation and Management (ECoWaste), King Mongkut’s University of Technology Thonburi (KMUTT), Thailand. Prior to the film synthesis process, the cassava bagasse samples were milled using a planetary mono mill (Fritsch, Pulverisette 6 classic line, Birkenfeld, Germany) at 300 rpm for 3 min. Later, the obtained powdered cassava bagasse was passed through a 425 µm sieve. The powder obtained after the sieving was then stored in a sealed container and kept at room temperature (22 ± 2 °C) until the film preparation was performed.

The combination of planetary ball milling and a tip sonication process was applied to obtain dolomite particles with a size reduced microcrystalline structure. First, the dolomite in powder form with 150 µm size was grinded into finer and small particle size by using the planetary ball mill with equipment model of PULVERISETTE 6 classic line (FRITSCH) (Bayern, Germany) for 10 h, with 19 repetitions at 500 rpm. The ball mill machine was initially filled with 50 stainless steel balls of 15 mm diameter. Then, the Digital Ultrasonic Disrupter model BRANSON 450 with lower section titanium micro tip (Queensland, Australia) was employed to provide ultrasonic shear effect for disaggregating and dispersing the dolomite particles using the tip sonication method. The dolomite:water ratio to form dolomite suspension was 1:10 (10 g of ball milled dolomite powder was added into 100 mL of distilled water). Dolomite suspension underwent the tip sonication process for 2 h with 30% of amplitude, while the pulse on value was 15 s and pulse off value was 10 s.