Table 5.
Thermal properties of natural composites obtained from DMA analysis.
| Fiber | Matrix | Thermal Properties | Ref. |
|---|---|---|---|
| Thermoset Matrices | |||
| Jute + sisal | Epoxy | The hybridization increased the storage modulus (E′) of composites. Tg of the hybrid composites was lower compared to pure jute composite. | [164] |
| Kenaf | Polyurethane (PU) | The acetylated treatment presented better values for storage modulus (E′) when compared with all other treatments. | [90] |
| Pineapple + kenaf | Phenolic | The treated pineapple fiber increased the Tg of the composites. | [52] |
| Mulberry | Polyester | 10% of NaOH treatment increased the storage modulus (E′) of the composite. The fibers decreased the Tg (values of 69 °C was found for the neat resin and 63 °C was found for the untreated composites). | [82] |
| Aloevera /Hemp/Flax | Epoxy | The hybridization and chemical treatment (BaSO4) increased the storage modulus (E′) and Tg of composites. | [180] |
| Kenaf + Nanofiller CNFs |
Epoxy | The incorporation of nanofiller improved the Tg of the composites and improved thermal stability and residual char of kenaf/epoxy composites. | [181] |
| Kenaf (KKK), Sisal (SSS) and Kenaf + Sisal (KSK and SKS) | Bio-Epoxy | The incorporation of fibers (sisal and kenaf) did not affect the Tg of the composites. The hybridization increased the values of storage modulus (E′) when compared to pure resin. | [166] |
| Jute + Nanoclay | Epoxy | The nanoclay modified jute composites presented higher E′, E″ and tan δ values. The composites modified with 5 wt% of nanoclay had improved viscoelastic properties. 5% treated jute fiber composites presented the highest E′ and E″ values but the lowest tan δ value. 5% NaOH + 5 wt% nanoclay specimens presented higher storage modulus and Tg. | [71] |
| Bamboo + Kenaf + Nanoclay |
Epoxy | The addition of the nanofiller improved the storage modulus, loss modulus and tan δ when compared to the other hybrid composite. | [182] |
| Ramie + Buriti | Polyester | The ramie reinforced composite treated with 2% de NaOH presented higher storage modulus and loss modulus compared to the other treated cases. | [84] |
| Jute + Oil palm |
Epoxy | High oil palm to jute fiber ratio lowered the storage modulus. Loss modulus presented an increasing trend as a function of increasing jute fiber content. | [141] |
| Bamboo + Kenaf | Epoxy | The complex and storage modulus of bamboo composite are higher compared to kenaf composite. Hybrid composites value lie between bamboo and kenaf composites. | [179] |
| Date palm + Bamboo | Epoxy | The hybridization of the composite presents an increase of storage modulus (E′) when compared with single fiber composites. | [69] |
| Buriti | Epoxy | The addition of buriti fiber improved the storage modulus (E′) and Tg when compared with pure epoxy. | [183] |
| Thermoplastic matrices | |||
| Flax + Basalt | PLA | The addition of natural fiber increased the storage modulus (E′) of the composites when compared to pure PLA composite. | [151] |
| Date palm | PVC and HDPE | The chemical treatments increased the properties of Tg and storage modulus (E′) when compared to untreated composites and pure matrix. | [70] |
| Sisal | PLA | The sisal fiber with 15% weight fraction increased the thermal properties with maximum storage (E′ = 3430 MPa) and maximum loss moduli (E″ = 245 MPa). | [184] |
| Bamboo, wood and coconut | PLA | The addition of natural fibers increased the crystalline degree of PLA matrix. Also, increased the storage modulus (E′) when compared with pure PLA. | [185] |
| sugar palm fiber (SPF)- and kenaf fiber (KF)- | Polypropylene (PP) | The hybrid composite with the best ratio (PP/SPF/KF), T-SP5K5, showed a loss modulus (E″) of 86.2 MPa and a damping factor of 0.058. | [61] |
| Ramie | PLA | The chemical treatments (NaOH and Silane) showed maximum storage modulus (E′) when compared to untreated composite. | [186] |
| Coir + pineapple leaf | PLA | The hybridization of the composite showed an increase of storage modulus (E′) and loss modulus (E″) when compared to pure PLA. | [187] |
| Carpinus betulus L. | PP | The incorporation of nanofiller increased the storage modulus (E′) and Tg when compared with pure PP. | [149] |
| Kenaf | PLA | The randomly oriented (ROFRPC) composite showed highest storage modulus (E′) when compared with unidirectional (UDFRPC) and bidirectional (BDFRPC) kenaf composites. The incorporation of different kenaf mats with PLA improved the Tg of the composites as compared to neat PLA. ROFRPC showed the highest value of Tg. | [188] |
| Basalt (BF) | PLA | The addition of BF improved the storage modulus (E′) when compared with pure PLA. Increasing the fiber content decreased tan δ (the presence of BF prevents the chain mobility of the pure PLA).The addition of BF had little influence on the Tg and Tm of the PLA composites. | [189] |