**3. Materials and methods**

#### **3.1 Materials**

 The grade of the Virgin polypropylene (PP) was H 605. The values for the PP properties presented in **Table 1** were provided by the Braskem Company.

The post-industrial polypropylene (PPr) was a washed and ground material supplied by the Poli Injet Company (Brazil), while the residue came from the packaging industry. The properties of PPr are: melt temperature (Tm) of 161°C, crystallinity degree (χc) of 32%, and melt flow index (MFI) of 4.83 g/10 min (230°C/2.16 Kg). The methodologies to evaluate these properties are described below.

The glass powder (GP) used in this study was supplied by the Massfix Company (Brazil) and is ground from windshield scraps. **Figure 1** shows the morphology of GP samples examined under a scanning electron microscope (SEM). The GP sample is composed of irregular-shaped particles with a broad size distribution.

Polypropylene modified with maleic-anhydride (PPMA), and Polybond 3200 with 1 wt% of maleic anhydride (MA) were supplied by the Chemtura Company (USA). The melt flow rate specified by the supplier is 115 g/10 min at 190°C under 2.16 Kg.

#### **3.2 Blend and composite preparation**

**Table 2** shows the compositions of the blends and composites. GP, PP, PPr, and PPMA were dried in an oven at 60°C for 24 h before extrusion. Next, each composition was processed in a twin-screw extruder (TeckTril, L/D = 36, screw diameter = 20 mm) at a screw speed of 400 RPM and temperature profile of 90/12 0/150/160/185/200/220/240/260/260°C. The materials underwent injection molding to produce appropriate specimens for stress and impact strength tests, which were performed according to ASTM D638 and ASTM D256 standards, respectively. Injection molding was carried out in an Arburg 270 S injection machine, using a


#### **Table 1.**  *Polypropylene H605 properties.*

#### **Figure 1.**  *SEM micrographs of glass powder (GP) particles.*


#### **Table 2.**

*PP, PPr, glass powder and PPMA blends and (or) composites composition.* 

temperature profile of 210/215/220/230/230°C. The injection and molding pressures were 1000 and 180 Bar, respectively. The mold temperature was 30°C, with a cooling time of 30 seconds.
