# New Polylactic Acid Composites Reinforced with Artichoke Fibers

^{*}

^{†}

## Abstract

**:**

## 1. Introduction

## 2. Experimental Section

#### 2.1. Materials

#### 2.2. Composite Preparation

**Figure 1.**Scheme of the manufacturing process to obtain PLA sheets and PLA/artichoke fiber laminates.

#### 2.3. Characterization

## 3. Results and Discussion

#### 3.1. Experimental Results

**Figure 2.**Stress-strain curves obtained from quasi-static tensile tests. UNID, unidirectionally; RANDOM, randomly.

**Figure 4.**SEM micrographs of the fracture surface of UNID composites at two different magnifications: (

**a**) scale bar 100 µm; (

**b**) scale bar 20 µm.

**Figure 6.**SEM micrographs of the fracture surface of the RANDOM composite. Red arrows indicate matrix-poor areas.

_{g}), evaluated as the temperature at which the damping [19,22] attains its maximum value, is influenced by the presence of artichoke fibers in the PLA matrix. In particular, the T

_{g}increases from 59 °C to 61.5 °C and 64 °C for RANDOM and UNID composites, respectively. Again, this trend can be associated with the decreased mobility of the matrix chains, due to the presence of the artichoke fibers [23].

#### 3.2. Hill’s Method for Tensile Modulus Prediction

_{L}) and transverse (E

_{T}) moduli, respectively:

_{f}and E

_{m}are respectively Young’s moduli of the fiber and matrix; ν

_{f}and ν

_{m}are the volume fractions of the fiber and matrix.

_{m}) is equal to 3.18 GPa. The tensile modulus of the artichoke fibers (E

_{f}), determined by performing tensile tests on dried long fibers, is equal to 19.7 GPa. The fiber volume fraction (ν

_{f}), evaluated considering the fiber weigh fraction (i.e., 10% for both composites) and the apparent densities of the PLA matrix and of the artichoke fiber, is equal to 0.081.

_{L}. On the other hand, Hill’s method allows one to calculate the theoretical Young’s modulus for random fiber-reinforced lamina (i.e., RANDOM composites) as follows:

_{L}(ν

_{f}) represents an upper bound in ideal conditions (i.e., perfect bonding, homogenous fiber and matrix, lack of voids), while E

_{T}(ν

_{f}) is a lower bound.

## 4. Conclusions

## Author Contributions

## Conflicts of Interest

## References

- Scalici, T.; Fiore, V.; Orlando, G.; Valenza, A. A DIC-based study of flexural behaviour of roving/mat/roving pultruded composites. Compos. Struct.
**2015**, 131, 82–89. [Google Scholar] [CrossRef] - Li, Y.; Mai, Y.W.; Ye, L. Sisal fibre and its composites: A review of recent developments. Compos. Sci. Technol.
**2000**, 60, 2037–2055. [Google Scholar] [CrossRef] - Biagiotti, J.; Puglia, D.; Torre, L.; Kenny, J.M.; Arbelaiz, A.; Cantero, G.; Marieta, C.; Llano-Ponte, R.; Mondragòn, I. A systematic investigation on the influence of the chemical treatment of natural fibers on the properties of their polymer matrix composites. Polym. Compos.
**2004**, 25, 470–479. [Google Scholar] [CrossRef] - Bledzki, A.K.; Reihmane, S.; Gassan, J. Properties and modification methods for vegetable fibers for natural fiber composites. J. Appl. Polym. Sci.
**1996**, 59, 1329–1336. [Google Scholar] [CrossRef] - Das, S.; Saha, A.K.; Choudhury, P.H.; Basak, R.K.; Mitra, B.C.; Todd, T.; Lang, S.; Rowell, R.M. Effect of steam pretreatment of jute fiber on dimensional stability of jute composite. J. Appl. Polym. Sci.
**2000**, 76, 1652–1661. [Google Scholar] [CrossRef] - Fiore, V.; Scalici, T.; Nicoletti, F.; Vitale, G.; Prestipino, M.; Valenza, A. A new eco-friendly chemical treatment of natural fibres: Effect of sodium bicarbonate on properties of sisal fibre and its epoxy composites. Compos. B Eng.
**2016**, 85, 150–160. [Google Scholar] [CrossRef] - Fiore, V.; Scalici, T.; Valenza, A. Characterization of a new natural fiber from Arundo donax L. as potential reinforcement of polymer composites. Carbohydr. Polym.
**2014**, 106, 77–83. [Google Scholar] [CrossRef] [PubMed] - Fiore, V.; Scalici, T.; Vitale, G.; Valenza, A. Static and dynamic mechanical properties of Arundo donax fillers-epoxy composites. Mater. Des.
**2014**, 57, 456–464. [Google Scholar] [CrossRef] - De Rosa, I.M.; Kenny, J.M.; Puglia, D.; Santulli, C.; Sarasini, F. Morphological, thermal and mechanical characterization of okra (Abelmoschus esculentus) fibres as potential reinforcement in polymer composites. Compos. Sci. Technol.
**2010**, 70, 116–122. [Google Scholar] [CrossRef] - Seki, Y.; Sarikanat, M.; Sever, K.; Durmuşkahya, C. Extraction and properties of Ferula communis (chakshir) fibers as novel reinforcement for composites materials. Compos. B Eng.
**2013**, 44, 517–523. [Google Scholar] [CrossRef] - Sarikanat, M.; Seki, Y.; Sever, K.; Durmuşkahya, C. Determination of properties of Althaea officinalis L. (marshmallow) fibres as a potential plant fibre in polymeric composite materials. Compos. B Eng.
**2014**, 57, 180–186. [Google Scholar] [CrossRef] - Fiore, V.; Valenza, A.; Di Bella, G. Artichoke (Cynara cardunculus L.) fibres as potential reinforcement of composite structures. Compos. Sci. Technol.
**2011**, 71, 1138–1144. [Google Scholar] [CrossRef] - La Mantia, F.P.; Botta, L.; Morreale, M.; Scaffaro, R. Effect of small amounts of poly(lactic acid) on the recycling of poly(ethylene terephthalate) bottles. Polym. Degrad. Stab.
**2012**, 97, 21–24. [Google Scholar] [CrossRef] - Botta, L.; Mistretta, M.C.; Palermo, S.; Fragala, M.; Pappalardo, F. Characterization and processability of blends of polylactide acid with a new biodegradable medium-chain-length polyhydroxyalkanoate. J. Polym. Environ.
**2015**, 23, 478–486. [Google Scholar] [CrossRef] - Fiore, V.; Botta, L.; Scaffaro, R.; Valenza, A.; Pirrotta, A. PLA based biocomposites reinforced with Arundo donax fillers. Compos. Sci. Technol.
**2014**, 105, 110–117. [Google Scholar] [CrossRef] - Scaffaro, R.; Botta, L.; Passaglia, E.; Oberhauser, W.; Frediani, M.; di Landro, L. Comparison of different processing methods to prepare poly(lactid acid)-hydrotalcite composites. Polym. Eng. Sci.
**2013**, 54, 1804–1810. [Google Scholar] [CrossRef] - Li, L.; Liu, X.; Zhou, X.; Hong, J.; Zhuang, X.; Yan, X. Mechanical properties of unidirectional continuous fiber self-reinforced polyethylene graded laminates. Polym. Compos.
**2015**, 36, 128–137. [Google Scholar] [CrossRef] - Charlet, K.; Béakou, A. Mechanical properties of interfaces within a flax bundle—Part I: Experimental analysis. Int. J. Adhes. Adhes.
**2011**, 31, 875–881. [Google Scholar] [CrossRef] - Shanmugam, D.; Thiruchitrambalam, M. Static and dynamic mechanical properties of alkali treated unidirectional continuous palmyra palm leaf stalk fiber/jute fiber reinforced hybrid polyester composites. Mater. Des.
**2013**, 50, 533–542. [Google Scholar] [CrossRef] - Fiore, V.; Di Bella, G.; Valenza, A. The effect of alkaline treatment on mechanical properties of kenaf fibers and their epoxy composites. Compos. B Eng.
**2015**, 68, 14–21. [Google Scholar] [CrossRef] - Martinez-Hernandez, A.L.; Velasco-Santos, C.; de Icaza, M.; Victor, M.C. Dynamic mechanical and thermal analysis of polymeric composites reinforced with keratin biofibers from chicken feathers. Compos. B Eng.
**2007**, 38, 405–410. [Google Scholar] [CrossRef] - Manikandan Nair, K.C.; Thomas, S.; Groeninckx, G. Thermal and dynamic mechanical analysis of polystyrene composites reinforced with short sisal fibres. Compos. Sci. Technol.
**2001**, 61, 2519–2529. [Google Scholar] [CrossRef] - Huda, M.S.; Drzal, L.T.; Mohanty, A.K.; Misra, M. The effect of silane treated- and untreated-talc on the mechanical and physico-mechanical properties of poly(lactic acid)/newspaper fibers/talc hybrid composites. Compos. Sci. Technol.
**2007**, 38, 367–379. [Google Scholar] [CrossRef]

© 2015 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons by Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

Botta, L.; Fiore, V.; Scalici, T.; Valenza, A.; , R.S. New Polylactic Acid Composites Reinforced with Artichoke Fibers. *Materials* **2015**, *8*, 7770-7779.
https://doi.org/10.3390/ma8115422

**AMA Style**

Botta L, Fiore V, Scalici T, Valenza A, RS. New Polylactic Acid Composites Reinforced with Artichoke Fibers. *Materials*. 2015; 8(11):7770-7779.
https://doi.org/10.3390/ma8115422

**Chicago/Turabian Style**

Botta, Luigi, Vincenzo Fiore, Tommaso Scalici, Antonino Valenza, and Roberto Scaffaro . 2015. "New Polylactic Acid Composites Reinforced with Artichoke Fibers" *Materials* 8, no. 11: 7770-7779.
https://doi.org/10.3390/ma8115422