Analysis of the thermal properties in short sansevieria cylindrica fibre/PLA composites processed by twin screw extruder followed by hot press molding technique

Short Sansevieria cylindrica fibre/polylactic acid composites (SCFP) were fabricated using a twin screw extruder followed by the hot press technique, with variations in fibre loadings of 10 wt%, 20 wt%, 30 wt% and 40 wt%. The thermal properties of SCFP were assessed through dynamic mechanical analysis (DMA), thermomechanical analysis (TMA), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Notably, the samples loaded with 40 wt% of fibre exhibited an increased storage modulus. In terms of loss modulus, the fibre-loaded samples displayed high values, indicating more heat is released during DMA experiment. Interestingly, the composite trend did not solely rely on increasing fibre loading, highlighting the intricate interplay between reinforcement and matrix crucial for determining viscoelastic properties across various temperatures. The TGA results revealed a decrease in inflection temperature with increasing fibre loadings, accompanied by a proportional rise in residues. The DSC thermograms indicated minimal differences in Tg, Tcc, and Tm values among composites with varying fibre loadings. However, neat PLA showed slightly higher values than the composites. On the other hand, reinforcing SCF into the PLA matrix promoted the crystallization of PLA by 1%–3% with the maximum degree of crystallinity of 25.4% obtained for 30 wt% of SCFP.


Introduction
In recent years, the demand for environmentally friendly products in all fields has increased rapidly because of the increased awareness of their benefits.As a result, biobased materials have become more common in the composite industry [1].Furthermore, researchers and manufacturers place the utmost importance on renewable and biodegradable materials to protect the environment and people's health in every possible way.Many industries, including aerospace, automotive, marine, food packaging, electronics, and transportation, are keen to utilise cellulose-based products in various applications [2].
Cellulose-based composites offer numerous advantages, including low density, cost-effectiveness, environmentally friendliness, good specific properties, ease of processing, and non-abrasiveness.Moreover, natural fillers-based reinforcements allow the ability to harness local resources in less industrialized countries, thereby improving materials and technologies while considering environmental impact [3].
Many authors have reported using natural fibres as reinforcements in thermoplastic matrices [4].Thermoplastics offer several advantages when used with natural fibres, including ease of processing (as thermoplastics can be melted and re-melted), better adhesion, low energy consumption, recyclability, ductility, and impact resistance [5].Additionally, many thermoplastic polymers that possess high thermal resistance have been developed.Thus, they are interested in the use of aerospace applications [6].
In this paper, short Sansevieria cylindrica fibres (SCF) were utilized as reinforcements in a PLA matrix.Fibrous plants are plentiful in tropical countries, and Sansevieria cylindrica, a wild plant native to Africa and Asia, belongs to the Asparagaceae family.Numerous researchers [7][8][9] have explored their applications in various fields.According to their findings, the extraction and processing of these fibres are straightforward, making them a commonly recommended choice for reinforcing lightweight materials.
Yu et al [10] investigated the linear coefficients of thermal expansion behaviour in various wheat straw/PP composites, ranging from 20 wt% to 65 wt%.The experiments were conducted at 20 °C to −13 °C and −13 °C to 60 °C.The results reported that increased wheat straw content contributed to a reduction in thermal expansion behaviour.For instance, samples loaded with 65 wt% wheat fibre exhibited ∼70% decrease in thermal expansion compared to those with 20 wt% wheat fibre.This result was ascribed to the capability of the reinforcement to restrict the deformation of PP molecular chains and hinder the flow of the plastic matrix.Zabihzadeh [11] investigated the thermal properties of wheat straw flour reinforced with high-density polyethylene (HDPE) and PP matrices.The study revealed that the type of matrix materials and the interfacial bonding between reinforcements and matrix materials significantly influenced the thermal properties.Moreover, the wheat straw/PP composites displayed lower thermal stability than the wheat straw/HDPE composites.Additionally, introducing maleic anhydride polypropylene (MAPP) and maleic anhydride polyethylene (mAPE) improved the results by enhancing the adhesion between wheat straw flour and matrix materials, consequently increasing thermal stability.
Yang et al [12] investigated the DSC and DMA behavior of natural fillers (rice husk and wood flour) reinforced with PP matrix.The DSC results indicated a notable influence of the addition of MAPP on the T g of the composites, attributed to the enhanced chemical bonding between the fillers and the matrix.However, the melting temperature of the composites remained unaffected by the presence of fillers.In the context of DMA, the storage modulus of biocomposites showed enhancements compared to the PP matrix.This improvement was observed as the fillers facilitated the transfer of stresses across the reinforcement to the matrix.Yılmaz and Akar [13] examined the TGA and differential thermal analysis of short rape fibres reinforced with three different matrices, namely HDPE, polystyrene and polyoxymethylene.The results showed that the rape reinforcement element burned before the matrix materials, resulting in a delayed burning process in thermoplastics.As a consequence, the rape-reinforced HDPE composites showed improvements in mechanical characteristics.Azammi et al [14] fabricated thermoplastic composites by varying the mixtures of kenaf fibre, natural rubber and thermoplastic polyurethane while maintaining a total weight of 40 g in each composite.The results reported that the natural rubber content in the composites influenced the overall weight loss and char residue.For instance, increased natural rubber content in the composites resulted in higher weight loss.Jumaidin et al [15] examined the impact of durian peel fibre/thermoplastic cassava starch composites on their thermal characteristics.The results revealed that the thermal behaviour of composites exhibited an increase, as observed by higher onset decomposition temperatures.Adding durian peel fibres contributed to an enhanced biodegradation rate, making the materials more environmentally friendly.Besides, the 40 wt% of durian peel fibre composites showed superior performance compared to other fibre-loaded samples.In another study, Ming et al [16] studied the effect of ternary composites of polybutylene adipate terephthalate/thermoplastic cassava starch/lignin.The results reported that adding lignin increased thermal stability and T g was also improved.This was evident in the increased thermal resistance of the composite materials.Besides, the lignin enhanced the interfacial compatibility between the polybutylene adipate terephthalate/ thermoplastic cassava starch.Hafila et al [17] explored the thermal behavior of thermoplastic cassava starch containing palm wax by varying its ratios from 2.5 wt% to 15 wt%.The TGA results showed that the thermal stability of thermoplastic cassava starch increased as the palm wax content increased.
Based on the extensive review of the existing literature survey, it was evident that no prior research had explored the thermal characteristics of SCFP.Considering this gap, the primary objective of this study was to investigate the impact of varying short SCF loadings: 10 wt%, 20 wt%, 30 wt% and 40 wt% on thermal characteristics of biocomposites.The fabrication of these composites is made by using a twin-screw extruder followed by hot press techniques.A comprehensive set of analyses was carried out to investigate the thermal behavior of these fabricated composites, encompassing dynamic mechanical analysis, thermomechanical analysis, thermogravimetric analysis, and differential scanning calorimetry.In conclusion, the short SCFP, exhibiting improved thermal characteristics, hold promise for applications as biodegradable materials.

Experimental
2.1.Materials SCF was collected from local sources in Hyderabad, India, while the matrix, polylactic acid (PLA) (grade INGEO 4043D) was purchased from Nature Friend Company Limited, Thailand.The essential properties of SCF and PLA are provided in tables 1 and 2.

Comparative analysis of fibre-reinforced composites
Table 3 compares the DMA, TGA, and DSC properties of composite materials with varying fibre lengths and loadings.
These observations showed that fibre length, fibre content, and fibre size significantly influence the thermal behavior of fibre-reinforced composites.Additionally, it was observed that optimum values or configurations vary for specific composite materials and their intended applications.Hence, it was decided to use micron-sized fibres ranging from 10 to 30 microns and lengths from 50 to 200 microns for examining the thermal behavior of SCFP by varying the fibre loadings from 10 wt% to 40 wt%.The details of composite fabrication are given below.

Fabrication of SCFP
Initially the SCFs were cut into micron-sized lengths using a specialized fibre micro-cutting machine (Universal cutting mill, Branch -Fritsch, Model-Pulverisette 19).The fibres used in the fabrication process appeared to have diameters ranging from 10 to 30 microns and lengths from 50 to 200 microns, which are typical for micronsized fibres used to reinforce polymer matrices.The fine micron-sized fibres were blended with a PLA matrix using a high-speed mixing machine (Unique tools, Model: 5L).Once the mixtures of fibres and PLA were prepared, they were carefully deposited into the hopper of a twin-screw extruder machine (XINDA, PSHJ-20) for the purpose of thorough blending.Detailed barrel temperature settings, including those for the feed zone, compression zone, melting zone, and die, can be found in table 4 for reference.
The resulting blend of fibre and matrix was then extruded into uniform mixtures, which were precisely cut using a strand pelletizer.A similar procedure was followed to produce filament extrusion ratios of 10 wt%, 20 wt%, 30 wt% and 40 wt% of SCFP.Before being introduced to the hot press machine, all the extruded mixtures were pre-heated in a hot air oven to remove moisture that may be presented in the fabricated samples.In the hot press molding machine, a temperature of 170 °C was maintained, with a pressure of approximately 2000 psi applied for 10 min.Following the molding process, the fabricated samples were left in a hot air oven at a temperature of 60 °C for 24 h for moisture removal.This step may help in improving the properties.Table 5 gives the details of fabricated samples.Subsequently, the samples underwent thermal tests to assess their performance.Table 6 gives the step-by-step procedure of composite fabrication.

Dynamic mechanical analysis (DMA)
The SCFP were subjected using DMA to investigate their viscoelastic behavior following ASTM D5418 [24].The DMA/SDTA861 e instrument from Mettler Toledo was used.The testing was carried out within ranges of 20 °C to 120 °C, maintaining a constant frequency of 1 Hz with a temperature ramp rate of 3 °C min −1 .Testing Fibre lengths varied: 20 cm, 30 cm and 40 cm DMA • An increase in fibre volume fraction and length helped enhance the thermal properties up to a fibre volume fraction of 40%. [19] Fibre volume fractions: 30%, 40% and 50% • 40 cm fibre length was the optimum fibre length in storage modulus.Wood flour, rice hulls, kenaf fibres, newsprint and polypropylene (PP) Fibre loading of 25% and 50% by weight DMA Increasing the fibre loading in PP helped enhance the storage modulus of composites.The same behavior of observed in all natural fibres and fibre content.These results indicate that the stiffness of the fibre-reinforced composites improved while the damping values were decreased. [20] Fibre length ranged from 1 mm to 4 mm TGA, DMA, DSC • The longer fibre-reinforced composites exhibited higher crystallinity.
Increased stiffness was correlated with improved crystallinity values. [21] • The storage modulus of composites increased by 82 to 90% using longer fibre-reinforced composites.• Variations of fibre length influenced minor changes in composite degradation, and their temperature differences, such as first-step and secondstep degradation temperatures, were less than 3 °C.• DSC results showed that the length of the hemp fibre did not affect the melting temperature of composites.• The crystallization temperature was decreased in composite samples.This was attributed to good fibre-matrix interfacial bonding.Besides, an increase in crystallinity was observed by increasing the fibre lengths.Wood flour, rice hulls, kenaf fibres, newsprint and high density polyethylene Fibre loading of 25% and 50% by weight TGA, DSC • Among the natural fibres, the kenaf fibres exhibited the least thermal stability, while the newsprint fibres showed improved thermal stability in the composites. [22] • Regarding the fibre loading, 50% of fibre-loaded samples exhibited faster degradation and higher weight loss than 25% of fibre-loaded samples.E glass/PP Fibre sizes varied from 1mm to 0.3 mm, and different fibre loadings were 10 wt%, 15 wt%, 20 wt% and 30 wt%

DSC
The activation energy increased with increasing fibre loading.This activation energy was required for crystallization in the composites.These results indicate that more energy was required to initiate the crystallization process. [23] samples had dimensions of 22 × 13 × 3 mm 3 (length × width × thickness) for dual cantilever mode.Storage modulus (E′), loss modulus (E″) and tan delta (tan δ) were determined for these fabricated samples.
where, α = Plot shows the dimensional changes against temperature variations, whereby the sample's expansion is linear within the temperature ranges T D at isobaric pressure 'p'.
L D = Dimensional change in the linear expansion region at temperature range T D and isobaric pressure 'p'.Li = Initial length of the fabricated composite sample.

Thermogravimetric analysis (TGA)
TGA measurements were conducted using a TGA/DSC 3+ thermogravimetric analyser (Mettler Toledo) with a 70 μl alumina ceramic holder following ASTM E1131 [26].The measurements were performed under a nitrogen atmosphere with a gas flow rate of 50 ml min −1 , a scanning rate of 10 °C min −1 , and a temperature of 25 °C to 600 °C.The mass of each sample ranged from 15 to 20 mg was used.

Differential scanning calorimetry (DSC)
The DSC Q2000 from TA instruments were employed to examine the DSC study of PLA and its composite samples using a 40 μl aluminium holder.The test was conducted according to ASTMD5418 [27] under a nitrogen atmosphere with a gas flow rate of 50 ml min −1 .During testing, the samples were subjected to temperature ranges between 0 °C to 240 °C at a rate of 10 °C min −1 .The mass of each sample ranged from 15 to 20 mg was used.

Dynamic mechanical analysis (DMA)
The DMA of short SCFP was examined to investigate their viscoelastic behaviour as a function of temperature.
During testing E′, E″ and tan δ were obtained by varying time and frequency.E′ gives the composites' stiffness or elasticity and exhibits how the composites' rigidity varies with respect to temperature.Moreover, it reveals elastic behavior by showcasing the energy stored in a viscoelastic material.This property is crucial for evaluating the suitability of composites for diverse applications [28,29].
Figure 1 shows the E′ of pure PLA and various fibre-loaded composite samples, with temperatures ranging from 20 °C to 120 °C.Notably, it was evident that the E′ of all the samples decreased as the temperature increased.This behaviour was ascribed to the softening effect of the matrix [30].PLA shows a relatively higher E′ (∼555MPa) at the lowest temperatures ranging from 20 °C to 25 °C (figure 1).This modulus value indicated that PLA was in a glassy state and in a rigid phase.In the glassy region, the relatively immobile polymer chains also exhibited solid-state behaviour [2].As the temperature increased, there was a decrease in the E′ due to the transition from a glassy region to a rubbery region at above >72°.This glass transition made the PLA chains more mobile, reducing stiffness [31,32].When the temperature was >118 °C, PLA′s E′ continuously decreased, indicating that the PLA became more flexible and the E′ reached a very low value (∼7MPa).During this stage, the segmental mobility of polymers further increased, or polymer chains even start to flow, and PLA exhibited a more significant loss of rigidity.20 wt% of fibre-loaded composite samples (i.e., 20 SP) consistently exhibited higher E′ than PLA samples due to the reinforcing effect of short SCFs.The composites showed improved stiffness and rigidity at lower temperature ranges [33].When the temperature was within the glass transition ranges, the 20 SP showed a greater E′ than PLA, because the fibres helped enhance the material's temperature stability (the SP 20 sample exhibited a residue of 4.03%, in contrast to PLA's 1.41% (TGA studies)).This higher residue indicates improved thermal stability, likely attributed to the reinforcing effect.Refer table 10 for detailed data) and stiffness in the glass transition phase.When the temperature was increased, the SP 20 continued to show higher E′.This behaviour indicated that it remained stiffer and rigid in the rubbery region.The stiffer and rigidity in the glassy region is advantageous in various applications that require both flexibility and strength [34].
Accordingly, the SP 30 samples consistently showed a higher E′ than PLA, SP 10 and SP 20.It was ascribed to increasing the fibre loading, which further enhanced the E′ and rigidity of respective composite samples.The SP 30 outperformed in the glass transition regions, highlighting the reinforcing effect of fibres.Thus, the composite materials maintained better stiffness in the glass transition region.Even at higher temperatures, the SP 30 continued to exhibit a higher E′, emphasized to resist softening (more resistance in polymer mobility due to the presence of fibres) than pure PLA samples.
The SP 40 showed the highest E′ throughout the temperature range.The higher fibre content increases the stiffness, making it the stiffest material among all the samples.The SP 40 also maintained a higher E′ in glass transition and rubbery regions.Sreenivasan et al [35] examined the E′ of SCF-reinforced polyester composite by varying fibre loadings from 10 wt% to 50 wt% (in increments of 10 wt%).Results reported that the 30 wt% of composite samples showed the highest E′ due to their better interfacial bonding between fibre and matrix.
The E″ represents the ability of SCFP to dissipate energy as heat, primarily attributed to frictional forces caused by the fiber and polymer.Figure 2 depicts the variations in E″ with the temperature of various fiberloaded composites.Notably, the pure PLA matrix displayed the lowest E″ value among the fabricated samples, owing to its limited heat dissipation capacity [36].
Furthermore, it was evident that the E″ of all the samples reached a peak value before decreasing as the temperature increased.This behavior was ascribed to increased molecular mobility within the polymer chains [28].In the case of composites, as the fibre loading increased, the E″ also increased.Remarkably, at higher temperatures (>68 °C), the difference in E″ between the SP 10 and PLA became more pronounced.The composite exhibited a higher E″, indicating that it retained its viscoelastic properties even at higher temperatures.However, a different trend emerged when fibre loading was increased in the PLA matrix.Table 7 gives the T g of various fibre-loaded samples.It is observed that T g of composite samples increased in most cases by increasing the fibre loading.
Tan δ is a dimensionless quantity in DMA, representing a damping characteristic of a material.It is the ratio of E″ to E′, quantifying energy dissipation to stored energy.For instance, if the tan δ value is higher, the material dissipates more energy as heat when subjected to stress.This characteristic is typical of a viscoelastic material in the rubbery region [28,34].Figure 3 illustrates the variation of tan δ with temperature for neat PLA and various composites fabricated by incorporating short SCF.In the case of neat PLA, two relaxation peaks are observed in   the tan δ curves.The primary relaxation peak curve occurred at a temperature of around 100 °C, which can be attributed to the T g of PLA.This peak marked the point at which the PLA transformed from a glassy, brittle state to a more flexible, rubbery state due to the increased molecular mobility of the PLA.Additionally, a 2nd transition was observed in figure 3, occurring around 117 °C.This observation was ascribed to changes in the movement of polymer chains within the crystalline region.These changes indicate the complex thermal characteristics of the material [35].
Table 8 shows the peak value of tan δ, glass transition temperature, and significant observations of neat PLA and its composite samples.For example, the T g of pure PLA sample is 100.85 °C.With an increase in SCFs within the PLA matrix, the T g of each composite sample increased and shifted towards higher temperatures.This shift towards higher temperatures is ascribed to the improved effectiveness of fibre reinforcement in PLA [37].
Additionally, the tan δ values were observed to decrease, possibly due to the improved interfacial bonding characteristics of fibre to the matrix.A decrease in tan δ values suggested enhanced interfacial bonding.Conversely, higher tan δ values at the interfaces indicated poorer interface adhesion, highlighting the significance of interfacial interactions in composite materials [38,39].

Thermomechanical analysis (TMA)
Figures 4(a), (b) depict the thermal expansion behavior of both neat PLA and composites reinforced with short Sansevieria cylindrica fibers.Thermal expansion refers to the material's dimensional change in response to temperature variations.The thermal expansion is reduced with the addition of fibers, this behavior is attributed to the interfacial adhesion properties between the fibers and matrix in composite materials.The enhanced interfacial properties reduce thermal expansion, suggesting less dimensional change [40].
Figure 4(a) reveals that the neat PLA matrix exhibited a more pronounced dimensional change as the temperature increased from 25 °C to 120 °C.Because the molecular chains within the polymer was moved vigorously with higher thermal energy, caused the material to expand.Consequently, the PLA matrix expanded, leading to an increase in its overall dimensions [41].
In contrast to this behaviour, the thermal expansion of composites reinforced with short SCFs was decreased, particularly in the case of SP 20.This observation can be ascribed to the restraining effect imposed on thermal expansion by the short SCFs [42].
In alignment with this observation, figure 3 shows that the SP 20 exhibited a low tan δ value (2.840).This value implied that the material is relatively stiff and has good elastic properties.Furthermore, composites characterized by low tan δ values typically exhibit increased resistance to deformation and damping when subjected to dynamic loads.In the context of thermal expansion behaviour, materials with low tan δ values are expected to give lower thermal expansion.Because they are less likely to deform or expand under temperature changes.They tend to retain their shape and dimensions, showing a more elastic response to temperature changes.Hence, the SP 20 exhibited the least thermal expansion compared to other samples due to their good interfacial properties and elastic behaviour, as reflected in their tan δ values.Figure 4(b) and table 9 show the coefficient of thermal expansion of PLA and its composite samples.It was evident that among the fabricated samples, SP 20 showed the lowest thermal expansion behavior at elevated temperatures.A lower CTE is preferable for materials in a wide range of applications where dimensional stability is critical, such as electronics and precision engineering.

Thermogravimetric analysis (TGA)
TGA is used to examine the thermal stability of polymers by monitoring the weight change of a polymer since the polymer is heated at a constant rate [43].This analysis provides data on thermal degradation.For instance, at what temperature the PLA and its composites start to decompose, rates of decomposition, etc The thermal stability of examined polymers and their composites is significant in determining the performance of PLA and composites for their intended applications.For instance, a material that has higher thermal stability may be  suitable for high-temperature applications without experiencing major degradation [44].The thermal stability of the SCFP was assessed through thermogravimetric analysis, and the thermograms depicting the temperaturedependent behavior of neat PLA and its composites with varying wt% of SCFP are presented in figure 5. Generally, the mass loss occurs in two or three stages depending upon the composite's fibre composition, such as removing the absorbed moisture, hemicellulose, lignin and cellulose components, and finally, the depolymerization of the matrix material [45].It is clearly evident from the primary and derivative thermograms that the decomposition temperature of the composites shifted to the lower side with an increase in the fibre contents.Increased fibre loading in composites can result in a significant rise in water molecules.The disintegration of molecules at the intermediate mass loss zone (between 200 °C and 400 °C) weakens the interface, accelerating composite breakdown [46].The thermal properties of PLA and its composites are presented in table 10.Table 10 shows that the inflection temperature decreases with increased fibre contents, whereas the residues increase with increasing fibre contents.This indicates the severe occurrence of coking and carbonization [46].Further from the thermograms of PLA and its composites, the mass loss drops significantly starting from the temperature range of about 260 to 300 °C, which may be attributed to the degradation of the material constituents.However, at higher temperatures, the structure of interactions between surfaces and the presence of components such as α-cellulose and lignin in the sansveria fibre may provide heat resistance.The fluctuation of these parameters in the composite is directly proportional to the wt% of sansveria fibres reinforced [47].As a result, the SP 40 suffered the least weight loss throughout the last stage of degradation.The weight percentage of char residue at 390 °C for PLA composites increased with the increase in SCFP content.This increase in the emergence of the char residue can be affirmed as an improved heat resistance exerted by SCFP.A similar kind of trend was also previously reported by researchers [35].

Differential scanning calorimetry (DSC)
The degree of crystallinity X % c ( )was estimated from the equation (2) shown below: H f D is the melting enthalpy (J/g) for the composite and H f 0 is the melting enthalpy for 100% crystalline PLA and w is the weight fraction polymer.
Figure 6 presents the DSC thermogram of the SCFP with respect to their fibre loading.T g , T cc , T m and degree of crystallinity obtained from the DSC thermogram has been tabulated in table 11.The infinitesimally small difference could be noticed in terms of T g , T cc , and T m values for the composites reinforced with various fibre loading.However, neat PLA was found to have slightly higher values than the composites.On the other hand, reinforcing SCF into the PLA matrix promoted the crystallization of PLA by 1%-3% with the maximum degree of crystallinity of 25.4% obtained for the SP30.The increase in the degree of crystallinity and a slight drop in T g , T cc and T m with the increase of fibre loading has been consistent with the findings reported in the recent studies with bamboo fibre, wood fibre, and coir fibre-reinforced PLA [48] and pulp fibre/PLA [49].The higher degree of crystallinity for composites up to 30 wt% is due to the fact that SCF acts as a nucleating agent, which increases the number of nucleation sites, leading to increased transcrystallinity and spherulite growth within the PLA matrix [50].

Conclusion
Examining the thermal properties of Short SCFP provided valuable insights into the impact of various fibre loadings.The key conclusions drawn from the results are outlined below.
Reinforcing the SCF into PLA led to a noticeable overall stiffness and rigidity enhancement, as evidenced by the increased E′ in the composites.Notably, SP 40 exhibited the highest E across the glass transition and rubbery regions.
At elevated temperatures (>68.5 °C), the SP10 exhibited a significant difference in E″, retaining higher viscoelastic properties.However, a distinct trend emerged with increased fibre loadings in the PLA matrix.
TGA thermograms revealed a substantial mass loss between 260 °C and 300 °C, indicating that the material constitutes degradation.In terms of weight loss during the final stage of degradation, SP 40 displayed the least weight loss, reporting a residue of 9.01%.
Minimal variations were observed in T g , T cc , and T m values among the fabricated samples, with the PLA consistently exhibiting higher values.Introducing SCF into PLA contributed to a 1% to 3% increase in crystallization values, reaching a maximum degree of crystallinity of 25.4% for the SP 30.
Incorporating SCF in PLA positively influenced their thermal characteristics, with varying fibre loadings showcasing distinct effects on stiffness, viscoelasticity, and crystallization behavior.These findings hold significance for tailoring SCFP for specific applications balancing thermal stability.

Table 3 .
Comparative study analysis on thermal properties of composites.
Banana stem, pineapple leaf, S-glass fibres and Epoxy resin

Table 4 .
Setting of barrel temperatures.

Table 5 .
Details of fabricated samples.

Table 6 .
Step-by-step procedure of composite fabrication.

Table 6 .
(Continued.) The PLA samples were moved to the next stage in twin-screw extruderThe PLA was melted using twin screw extruder and extruded filaments were formed 7Mater.Res.Express 11 (2024) 035506 S Krishnasamy et al

Table 6 .
(Continued.) PLA was deposited over the moldThe PLA was filled in mold and loaded in hot press moulding machine at 170 °C for 10 min Fabricated samples

Table 7 .
Glass transition temperature of SCFP.

Table 8 .
Tan δ and T g of various SCFP.

Table 9 .
Coefficient of thermal expansion of PLA and various SCFP.