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Materials Science in Additive Manufacturing Cellulose microfiber in ABS filament for 3D printing

Figure 10. Stress versus strain curves of specimens in flexion test. Left: Pure ABS; Right: ABS/cellulose microfiber.
ABS: Acrylonitrile butadiene styrene; CP1–CP5: Specimens name; AVG: Average.

Table 1. Results of the traction test weight). Five specimens of pure ABS and five specimens
of ABS in composite with crystalline cellulose microfiber
Sample Elastic Stress Strain were formed.
modulus at break at break
(MPa) (MPa) (%) The average elastic modulus obtained is quite similar
Pure ABS 274.2±25.6 17.1±1.8 16.0±2.6 and overlap almost completely within the error ranges. The
ABS/cellulose microfiber 272.0±14.7 19.0±1.1 26.0±2.7 stress at break behaves in a similar way. Differently, the strain
ABS: Acrylonitrile butadiene styrene at break was substantially higher, at approximately 10%. In
the flexion test, it was possible to observe an increase in the
elastic modulus of ABS with microfibers, as well as in the
Table 2. Results of the flexion test
tension at break. The strain at break had a different behavior,
Sample Elastic Stress Strain being smaller in the composite. Both materials exhibited
modulus at break at break approximately similar impact strength results, with a
(MPa) (MPa) (%) slightly lower value for the microfiber-polymer composite,
Pure ABS 1285.0±173.7 11.9±3.3 15.2±3.1 but equivalent within the experiment’s error range. The melt
ABS/cellulose microfiber 1522.0±98.1 14.1±5.6 12.3±0.7 flow index of both materials (7 g/10 min) is substantially
ABS: Acrylonitrile butadiene styrene higher than that of the ABS pellets (4.43 g/10 min). This
indicates a decrease in the polymer molar mass. There was
Table 3. Impact test results (average of all specimens) probably degradation in the polymer properties during
processing. Furthermore, ABS with cellulose microfibers
Sample Impact resistance (kJ/m ) was more fluid than pure ABS.
2
Pure ABS 11.5±1.9
ABS/cellulose microfiber 10.2±1.0 6. Conclusions
ABS: Acrylonitrile butadiene styrene The hydrolysis of E. grandis (from certified wood) with
nitric acid (5.0 mol/L) was successful in isolating highly
4.4. Flow rate index crystalline (84.4%) cellulose microfibers. At a content of
0.5% (in weight) of crystalline cellulose microfiber, it was
The supplier (3DLab) certifies that the melt flow index of possible to identify an increase in the strain at break in the
ABS pellets is 4.43 g/10 min. The results obtained were traction test. There was an increase in elastic modulus and
7.430 g/10 min for pure ABS and 7.546 g/10 min for ABS stress at break in the flexion test and a very slight reduction
with crystalline cellulose microfiber. in impact strength. The fluidity increase of both samples
5. Discussion was quite relevant compared to the standard established
by the manufacturer of the commercial polymer. This
This section discusses the results of the mechanical fluidity is probably an indicator of polymer degradation.
characterization of test specimens formed by 3D printing. As there were two processing steps, the conformation of
Crystalline cellulose in microfibers was successfully the filaments and the 3D printing, it is believed that the
obtained and served as an additive to ABS at 0.5% (in degradation is associated with the overlap of treatments.

Volume 2 Issue 2 (2023) 6 https://doi.org/10.36922/msam.1000