**3.1 Treatment of brittle plastics**

The plates of polymethyl methacrylate (PMMA) plastic preliminarily cut into pieces with the dimensions of length 100 mm, width 100 mm and thickness 3–5 mm were reprocessed by the disintegrator milling.

The reprocessing technology of the PMMA plastic in the disintegrators consisted of three stages:


The main kinetic parameter when processing the material in disintegrators is the specific treatment energy of *E*<sup>S</sup> in kWh/t, which is important both from the point of view of the milling effect (grindability) and from the economic side of the process [10]. Grindability of PMMA plastic as a function of particle size of the specific energy of treatment was analyzed.

The powder particles size after preliminary, intermediate multi-step and final millings of the PMMA plastic are briefly given in **Figure 4**.

#### **Figure 4.**

*Dependence of the median particle size d50 of the PMMA plastic powder on the specific energy of treatment ES [9].*
