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Abstract

Composites of a recycled polyvinyl chloride-styrene-co-acrylonitrile copolymer (rPVC-SAN) blended with a date palm fiber ratio of 30% by weight were produced. The composites were analyzed using combined thermogravimetric analysis (TGA)/differential thermal calorimetry (DSC) and dynamic mechanical analysis (DMA) to investigate their thermal and viscoelastic characteristics. Alkaline, silane, and combination alkaline-silane (ASiDF) treatments were assessed for fiber-matrix adhesion. A combination of melt-compounding techniques and hot-pressing molding was employed to create both untreated and treated composites. A thermal analyzer and a dynamic mechanical analyzer were used to test the thermal and DMA parameters of the composites, including glass transition temperature, storage modulus, loss modulus, initial thermal degradation temperature (Tonset), and maximum temperatures (Tmax1 and Tmax2). Compared to other treated composites, rPVC-SAN-ASiDF exhibited the greatest storage and loss moduli but the lowest peak damping factor. Cole-Cole analysis indicated a homogeneous distribution of fibers due to miscibility. This study demonstrated that rPVC-SAN composites reinforced with date palm fiber exhibited significant improvements in thermal and dynamic mechanical characteristics when enhanced by a combined ASiDF fiber treatment. The SAN concentration at the fiber-matrix interface increased during the extrusion process due to chemical interactions between the alkoxyl groups on 3-aminopropyltriethoxysilane and the nitrile groups on SAN, in addition to cross-linking between rPVC and SAN. The modified fibers positively influenced the DMA and thermal properties of the thermoplastic blend composites. Overall, the results indicated that composites suitable for automotive components exhibited enhanced thermal and dynamic performance when reinforced with a thermoplastic blend that included treated date palm fibers.

Keywords

Recycled polyvinyl chloride styrene-co-acrylonitrile copolymer date palm fibers viscoelastic behavior

Introduction

The use of eco-friendly materials, such as bio-based plastic composites, has recently gained popularity both in Algeria and globally. Molding, extrusion, and injection molding processes are methods for creating biocomposites from primary raw materials, including recycled plastic, wood waste, and a percentage of additives.^1,2

Over the past few decades, polymers have replaced numerous traditional materials, such as metals, in many applications. Polymers are viable alternatives due to their advantages over more conventional materials.^3,4

After polyethylene and polypropylene, polyvinyl chloride (PVC) is the most widely available general-purpose plastic. PVC is extensively utilized in construction, pipelines, films, and insulation due to its durability, fire resistance, low heat conduction, and high insulating capacity.^5,6 However, PVC’s low application temperature and tendency to fracture from brittleness limit its applications. The low degradation temperatures of commercially rigid PVC result in insufficient modulus values above approximately 100°C. Effective mechanical properties at elevated temperatures are essential for electrical and electronic equipment and many industrial devices. The limitations of PVC at high temperatures necessitate new control standards for tubes and pipes.

Polymer blends leverage the properties of all included polymers to produce an improved final product.^7,8 However, the low entropy, however, implies that most polymer pairs cannot be mixed effectively. This often results in the formation of disconnected phases between the two polymer phases, leading to a rough phase morphology and inadequate mechanical characteristics.^9,10

To enhance the blend’s impact characteristics, styrene-co-acrylonitrile (SAN) is sometimes added to the brittle matrix.^11,12 Due to its excellent weathering properties, SAN copolymer plays a crucial role in several industries.¹³ Tian et al.¹⁴ Demonstrated that SAN/polyurea nanocomposite foams exhibited improved processability and excellent heat resistance. Liao et al.¹⁵ reported that styrene acrylonitrile and ammonium polyphosphate could enhance the mechanical and thermal properties of polypropylene composites. Additionally, other studies have investigated the use of SAN as a reinforcement agent in polymeric materials.¹⁶ Liu et al¹⁷ and Garcia et al¹⁸ explored the potential compatibility of recycled poly (vinyl chloride)/styrene-acrylonitrile blends.

The Saharan date palm tree (Phoenix dactylifera L.), a member of the Arecaceae family, has been identified as a potential lignocellulosic reinforcement.^19,20 This novel type of lignocellulosic biomass is derived from the rachis and leaflets of the date palm tree. The fiber from this tree is an excellent renewable waste material for reinforcing composites, and the tree can be found in abundance across the Saharan region.^21,22 Date palm fibers (DFs) have been the subject of numerous experiments on chemical extraction and identification,^23,24 but have seen limited applications as reinforcement materials for polymers, particularly in polymer blends.

While DFs have been used as reinforcement in polymer blends, this is rarely documented in the literature. This absorption complicates the even distribution of wood fibers throughout the polymer matrix during the melt blending process. Chemical treatments, including alkali and silane treatments, may improve compatibility between the natural fiber and the polymeric matrix, enhancing the thermal and physical characteristics of biocomposites. Specifically, chemical treatment can remove lignin and hemicellulose while increasing the amount of crystalline cellulose.^25,26 Besides the specific properties of their constituent parts, the properties of composite materials made from DFs are also influenced by the interfacial bonding between the fibers and their matrix.^27,28 As plant fibers contain hydrophilic hydroxyl groups, they absorb significant amounts of water when used in composites.^29,30 This absorption complicates the even distribution of wood fibers throughout the polymer matrix during the melt blending process. Chemical treatments, including alkali and silane treatments,^31,32 may improve compatibility between the natural fiber and the polymeric matrix, enhancing the thermal and physical characteristics of biocomposites. Specifically, chemical treatment can remove lignin and hemicellulose while increasing the amount of crystalline cellulose.^33,34

Most importantly, they are cheap, light, productive, and easy to make biocomposites. However, as awareness of the environmental damage caused by petroleum-based polymer compounds grows, and as the prices of petroleum products rise, companies are striving toward a circular economy by employing techniques such as mechanical recycling.^35,36 The use of recycled PVC to create value-added products can not only address the ecological issue of plastic waste but also provide economic advantages. Together, we will explore environmentally friendly alternatives that can be incorporated into PVC polymers to mitigate their harmful environmental effects.^37,38

Recently, Kakhk et al. demonstrated that synthesized core-shell acrylonitrile-styrene-acrylate (ASA) particles were suitable for toughening PVC due to their high compatibility with PVC polymer, increased impact strength, elastic modulus, and heat distortion temperature.³⁹ Moreover, ASA is characterized by a core-shell structure, with a soft core made of poly (butyl acrylate) and a hard shell made of styrene-acrylonitrile (SAN) copolymer. However, when the percentage of poly (butyl acrylate) in ASA increases, the tensile and flexural strengths of PVC/ASA blends tend to decrease.⁴⁰ In this work, we successfully produced a biocomposite with outstanding thermal and dynamic mechanical properties compared to most existing biocomposites, utilizing commercial SAN and rPVC as the matrix, reinforced with 30 wt% alkali, silane, and alkali-silane treated DFs as biofillers.

Experimental

Materials

The rPVC material was sourced from recycled PVC cables collected from entreprise nationale d’industrie de cable biskra (ENICAB’s) waste. Before use as a matrix, PVC cables were ground, sieved through a 1 mm sieve, washed in a soapy water solution, and dried overnight in a vacuum oven. Table 1 displays the physical and mechanical properties of the recycled PVC used in this research.

Table 1.

The mechanical and physical properties of the rPVC.

Properties	rPVC
Tensile strength (MPa)	20.34 ± 0.9
Tensile modulus (MPa)	380 ± 12
Tensile strain (%)	26 ± 4
Density (g/cm³)	1.39

The French company Sigma-Aldrich supplied the SAN with a 28% acrylonitrile content, average molecular weight of 180 kg/mol, and glass transition temperature of 106°C, along with sodium hydroxide (NaOH), acetic acid (CH₃COOH), and 3-aminopropyltriethoxysilane (APTES).

DFs were harvested from date palm trees in southern Algeria.

Extraction Technique of DFs

The collected DFs were first cleaned of dust by repeatedly rinsing them with water. Then, the fibers were mechanically agitated in a 2 L glass container while immersed in 80°C water for 2 hours to remove wax and contaminants. Subsequently, they underwent a 4-day drying period at 65°C in an air oven. Once dried, the fibers were ground into a powder using a coffee grinder (Moulinex AR11, France) and sieved to achieve different particle sizes (<350 μm).

Surface Modification of DFs

To improve fiber-matrix interaction, we applied three treatments to the DFs to increase the cellulose content. These modifications are detailed below.

Alkalization of DFs

Rinsing DFs with an alkaline solution removes some lignin and other chemicals from the surface of the DF. After rinsing with water, the DFs were immersed in a 5 wt% NaOH solution in a 2 L glass beaker at room temperature for 24 hours. After thorough washing with water, we neutralized the fibers by submerging them in a 1% CH₃COOH solution following the extraction process. The modified DFs were collected using filtration and dried at 65°C for 48 hours.

Silanization of DFs

To enhance the fiber-matrix interface strength, we applied silane to the DFs using APTES. A 90:10 (v/v) mixture of ethanol and water was prepared and stirred for 20 minutes. The pH of the solution was adjusted with CH₃COOH while stirring, and the silane (3.5 wt% based on DF concentration) was gradually added to ensure uniform distribution. Hydrolysis was then performed for 3 hours at room temperature. Subsequently, the DFs were added to the mixture and allowed to rest at room temperature for 3 hours. Following silanization, we rinsed the fibers repeatedly in a 90:10 (v/v) ethanol/water solution to remove any remaining silane. After we completed the treatment process, the fibers were filtered and dried for 48 hours at 65°C.⁴¹

Combination Alkali/Silane Treatment for DFs

Additionally, the DFs underwent an alkali treatment followed by silanization. The alkali treatment with NaOH was conducted first, followed by chemical modification with silane, as previously described. After we completed the treatment process, the fibers were filtered and dried for 48 hours at 65°C.^42,43

Fabrication of the rPVC-SAN-DF Composites

The three DF fiber treatments incorporated into rPVC-SAN-DF composites are shown in Table 2. The rPVC and SAN polymers, along with the treated DF, were manually mixed until smooth. Composites of rPVC-SAN and treated DF were produced using a twin-screw extruder. The process was performed in three distinct zones at temperatures of 165, 170, and 175°C, with a speed of 50 rotations per minute. In the lab, a grinder and a device for collecting extrudates were employed. The material was then compressed in a hydraulic hot press at 170°C and 300 bar pressure. Once the rPVC-SAN-DF composites had been heated to high temperatures, they were allowed to cool to room temperature before being milled using a numerically controlled milling machine. Figure 1 presents the different steps of composite preparation, and Table 2 displays the relative amounts of rPVC-SAN and fiber used to produce the various rPVC-SAN-DF composites.

Table 2.

Sample code of different compositions for rPVC-SAN-DF composites.

Composite sample	rPVC (%)/SAN (%)	DF (%)
rPVC-SAN-UDF	50/50	30
rPVC-SAN-ADF	50/50	30
rPVC-SAN-SiDF	50/50	30
rPVC-SAN-ASiDF	50/50	30

Figure 1.

Different steps for manufacturing rPVC-SAN-DF composites.

Characterization of Composite

Thermal Analysis

The rPVC-SAN-DF composites were thermally examined using a TGA/DSC STARE thermal instrument (Mettler Toledo) with a heating rate of 10°C/min and a temperature range of 20–600°C in a nitrogen atmosphere.

Dynamic Mechanical Analysis (DMA)

DMA is a technique used to study the mechanical characteristics of materials as a function of duration, temperature, and sinusoidal frequency. DMA was performed on the rPVC-SAN-DF composites using a DMA Q800 machine manufactured by TA Instruments. The temperature experienced a linear rise at a rate of 5°C per minute over the temperature range of 25 to 120°C, while the frequency remained constant at 1 Hz. The dimensions of the specimen were measured to be 60 mm × 10 mm × 2 mm.

Results and Discussion

TGA of rPVC-SAN-DF Composites

The thermal properties of the rPVC-SAN-DF composites were evaillustrating the weight loss from 25°C to 600°C (Figure 2). The decomposition temperature and char yield are summarized in Table 3. The rPVC-SAN-DF composites exhibited three degradation steps. All rPVC-SAN-DF composites displayed an initial weight loss at around 140°C due to water evaporation. The Tonset of the rPVC-SAN-DF composites increased in the order of rPVC-SAN-UDF (259.6°C) < rPVC-SAN-ADF < rPVC-SAN-SiDF < rPVC-SAN-ASiDF (273.32°C).³⁴ The higher Tonset for the rPVC-SAN-ASiDF composite suggests that the combined alkali and silane treatment enhanced the interfacial interaction between the matrix and the DF, thereby improving the thermal performance of the rPVC-SAN-ASiDF composites. This enhancement can be attributed to the reaction of alkoxyl groups in excess silane with the nitrile group of SAN and the cross-linking of rPVC and SAN during the extrusion process, increasing the SAN concentration at the fiber-matrix interface and enhancing the molecular entanglement.⁴⁴

Figure 2.

TGA curves of rPVC-SAN-DF composites.

Table 3.

The decomposition temperatures and char yield for rPVC-SAN-DF composites.

Composite	T at 5% (°C)	T at 30% (°C)	T at 50% (°C)	T_{max 1} (°C)	T_{max 2} (°C)	Residue at 600°C (%)
rPVC-SAN-UDF	259.60	327.15	411.66	284.29	413.19	21.19
rPVC-SAN-ADF	267.81	318.25	409.10	286.09	412.75	20.24
rPVC-SAN-SiDF	269.88	320.99	410.72	268.68	420.23	21.31
rPVC-SAN-ASiDF	273.32	323.72	413.66	286.33	420.51	20.36

DTG Results of rPVC-SAN-DF Composites

Figure 3 displays the DTG curves, the pyrolysis temperatures Tonset, T_Max1, and T_Max2 of the rPVC-SAN-ASiDF composite were higher than those of the other composites, indicating an increase in thermal stability. Within the temperature range of 280°C–300°C, all rPVC-SAN-DF composites exhibited a loss of mass, from the release of gaseous byproducts such as hydrogen chloride, ammonia, and hydrogen cyanide,¹¹ as well as the thermal degradation of holocellulose.²⁶ The thermal degradation of the composites in the temperature range of 400°C to 450°C was similar to the previous step, indicating the complete degradation of the polymer blend and lignin.⁴⁵ The residues were also very close for all composites.

Figure 3.

DTG behavior of rPVC-SAN-DF composites.

DSC of the rPVC-SAN-DF Composites

Figure 4 displays the DSC curves of rPVC-SAN-DF composites treated using various procedures. The treated DF acts as a heterogeneous nucleating agent, accelerating the nucleation rate and increasing the cold crystallization temperature in rPVC-SAN-UDF and rPVC-SAN-ADF composites. The glass transition temperature (Tg) is significantly influenced by the alteration of silane-coupling agents in rPVC-SAN-SiDF and rPVC-SAN-ASiDF composites, indicating that the coupling agents affect intramolecular contacts and lamellar crystal structure. The silane coupling agents provide effective interfacial contacts between rPVC-SAN and DF, controlling the motions of blend chains. The rPVC-SAN-ASiDF composite exhibits a higher Tg compared to composites with ADF or SiDF (see Table 4, which contains the DSC data). Incorporating ASiDF reduces the crystallinity of the composites, disrupting the regularity of the rPVC-SAN and hindering crystallization. The melting point (Tm) of rPVC-SAN-DF composites is relatively insignificant. However, the rPVC-SAN-ASiDF composite shows substantially improved in melting peak area, indicating reduced crystallization.^46,47 This improvement suggests that during the extrusion process, SAN becomes more abundant at the fiber-matrix interface due to a chemical reaction between the alkoxyl groups on APTES and the nitrile groups on SAN, thereby enhancing surface compatibility.⁴⁴

Figure 4.

DSC curves of rPVC-SAN-DF composites.

Table 4.

Tg and Tm from DSC curve for rPVC-SAN-DF composites.

Composite	Tg from DSC (°C)	Tg from Tan δ (°C)	Tg from LM (°C)	Tm (°C)
rPVC-SAN-UDF	64.49	68.70	56.23	164.46
rPVC-SAN-ADF	70.13	71.71	65.02	163.37
rPVC-SAN-SiDF	69.54	79.36	51.54	161.31
rPVC-SAN-ASiDF	74.01	82.91	68.70	162.69

Viscoelastic Results of rPVC-SAN-DF Composites

Storage Modulus

Figure 5 illustrates the effects of the three types of fiber treatment undergone by the DFs on the storage modulus of the resulting rPVC-SAN-DF composites. The storage modulus values of the composites containing DFs subjected to alkaline treatment (rPVC-SAN-ADF), silane treatment (rPVC-SAN-SiDF), and combined alkaline-silane treatment (rPVC-SAN-ASiDF) are compared with the composite reinforced with untreated fiber (rPVC-SAN-UDF). DMA measures the stiffness, matrix/fiber interfacial bonding, degree of cross-linking, and damping properties of materials.^27,45 Stiffness primarily depends on the mechanical properties of the composites and their dimensions. The evolution of storage modulus as a function of temperature for both untreated and treated fiber composites is presented in Figure 5. The graph reveals a decreasing trend in storage modulus with increasing temperature. Notably, the storage modulus of rPVC-SAN-ASiDF reached a very high value, while the values for rPVC-SAN-ADF, rPVC-SAN-SiDF, and rPVC-SAN-UDF were similar at low temperatures. Rising temperature determines chain mobility, leading materials to lose close structural packing until the rubbery plateau region is reached. The maximum value of storage modulus was observed for rPVC-SAN-ASiDF, while the minimum was for rPVC-SAN-UDF. As shown in Figure 5, rPVC-SAN-UDF exhibited the lowest storage modulus and rubbery phase, indicating materials with flexible properties and a low degree of stiffness. It is also important to clarify that, in the glassy state, the storage modulus is influenced by the packing of the polymer chain system and the intermolecular forces of the material.⁴⁸

Figure 5.

Storage modulus performances of rPVC-SAN-DF composites.

Loss Modulus (LM)

The loss modulus measures the energy dissipated or lost as heat per cycle of sinusoidal deformation when comparing various systems at the same strain amplitude.⁴⁹ It represents the viscous response of materials. Figure 6 illustrates the variation of the loss modulus with different surface modifications undergone by the DFs. The peak of the loss modulus curve indicates the highest heat dissipation, occurring at the temperature where the loss modulus is highest, reflecting the Tg of the system. The broadening curve observed for all samples indicates an inhibited relaxation process in the composites. The values of the loss modulus followed the increasing trend: rPVC-SAN-UDF < rPVC-SAN-ADF < rPVC-SAN-SiDF < rPVC-SAN-ASiDF (Table 5). This phenomenon can likely be explained by increased internal friction, enhancing theenergy dissipation in the composites. Moreover, among the treated composites, rPVC-SAN-ASiDF recorded the highest Tg. The effect of surface fiber modification was demonstrated by the highest Tg value for rPVC-SAN-ASiDF, followed by rPVC-SAN-ADF, rPVC-SAN-UDF, and rPVC-SAN-SiDF composites.

Figure 6.

Loss modulus performances of rPVC-SAN-DF composites.

Table 5.

Peak height of Tan δ, SM, and LM curves and residue at 700°C for rPVC-SAN-DF composites.

Composite	Peak of Tan δ	Peak of SM (MPa)	Peak of LM (MPa)
rPVC-SAN-UDF	0.85	3275.19	277.0
rPVC-SAN-ADF	0.96	3396.31	275.31
rPVC-SAN-SiDF	0.84	3391.24	244.66
rPVC-SAN-ASiDF	0.83	3644.08	235.93

Damping Factor (Tan δ)

The damping factor can be correlated to the impact resistance of materials and is generally influenced by the incorporation of fibers in a composite system. This action is attributed to the shear stress concentration at the fiber ends, combined with the additional viscoelastic energy dissipated in the matrix material. As seen in Figure 7(a) the rPVC-SAN-ASiDF showed a lower curve, followed by rPVC-SAN-SiDF, rPVC-SAN-UDF, and rPVC-SAN-ADF. A lower value of tan δ indicates good interfacial bonding between the fiber and the matrix of the composites.⁵⁰ In contrast, higher tan δ values suggest poor interfacial bonding. Thus, closer packing of the fibers will prevent crack propagation due to/the presence of surrounding fibers.⁵¹ The most effective fiber treatment, leading to the best stress transfer, was noted for the rPVC-SAN-ASiDF composites. This result is consistent with the storage modulus of rPVC-SAN-ASiDF composites. Similar studies on alkaline-silane treated DFs hybrid composites reported lower damping values over a wide temperature range.³³ The Tg are presented in Table 4. Tg is derived from the maximum of the tan δ curve, typically interpreted as the peak of tan δ curves obtained during DMA tests. The Tg for all composites range from 79°C to 95°C. The rPVC-SAN-ASiDF composites revealed a higher Tg and lower relaxation compared to the rPVC-SAN-ADF, rPVC-SAN-SiDF, and rPVC-SAN-UDF samples, as summarized in Table 4. Additionally, the maximum tan δ of the rPVC-SAN-UDF, rPVC-SAN-ADF, rPVC-SAN-SiDF, and rPVC-SAN-ASiDF composites was 0.85, 0.96, 0.84, and 0.83, respectively, while the Tg of the rPVC-SAN-UDF, rPVC-SAN-ADF, rPVC-SAN-SiDF, and rPVC-SAN-ASiDF composites was 68.7°C, 71.71°C, 79.36°C, and 82.91°C, respectively. The higher Tg of the rPVC-SAN-ASiDF composite indicates better interfacial adhesion between the ASiDF and rPVC-SAN matrix while illustrating an important limitation of interfacial mobility in composite systems. This finding also agrees with results obtained by other researchers for treated jute-fiber-reinforced thermoplastic polyurethane (TPU) composites.⁵²

Cole–Cole Plots

Cole–Cole plot mapping of DMA data is a useful method for determining the viscoelastic properties of polymeric materials. Additionally, the Cole–Cole plot is utilized to understand the structural changes in cross-linked polymers after incorporation fiber reinforcement in the polymer matrix.⁵³ Figure 7(b) depicts the Cole–Cole plots of loss modulus (E″) versus storage modulus (E′) of rPVC-SAN-UDF, rPVC-SAN-ADF, rPVC-SAN-SiDF, and rPVC-SAN-ASiDF composites. Previous studies have indicated that the homogeneity of a system can be detected from the nature of the Cole–Cole plot.⁵⁴ Homogeneous polymeric systems typically display a perfect semicircle diagram.⁵⁵ As observed in Figure 7(b), the curve shapes of rPVC-SAN-SiDF and rPVC-SAN-ASiDF composites demonstrate a perfect semicircular curve, indicating homogeneous polymer composites and good adhesion between the fiber and the matrix. This finding is attributed to the increased abundance of SAN at the fiber-matrix interface due to a chemical reaction between the alkoxyl groups on APTES and the nitrile groups on SAN, along with the cross-linking of rPVC with SAN, thereby enhancing surface compatibility. The Cole–Cole curves of these composites are higher than those of the rPVC-SAN-UDF and rPVC-SAN-ADF composites, providing strong evidence that surface modification enhanced fiber-matrix bonding.

Figure 7.

(a) Viscoelastic and (b) cole-cole plot behaviors of rPVC-SAN-DF composites.

Conclusions

This investigation elucidated the intricate relationship between the thermal and dynamic mechanical properties of rPVC-SAN composites reinforced with DF, contingent upon the specific treatment applied to the DF. Analyzing storage modulus values across various treatments revealed the superior performance of alkaline-silane treated fibers. Notably, composites incorporating rPVC-SAN and ADF showcased the highest peak loss modulus values, followed by counterparts employing UD-F, SiDF, and ASiDF. The advantageous effects of DF treatment were evidenced by a discernible reduction in tan δ values for rPVC-SAN-ASiDF composites, indicate enhanced interfacial adhesion between the fiber and the rPVC-SAN blend. Remarkably, the combined alkaline-silane treatment significantly improved thermal and dynamic mechanical characteristics. This enhancement is attributed to the augmented SAN concentration at the fiber-matrix interface during extrusion, facilitated by chemical interactions between alkoxyl groups on APTES and nitrile groups on SAN, alongside cross-linking between rPVC and SAN. The observed perfect semicircular curves in the Cole-Cole plots of treated fibers signify the formation of homogeneous polymer composites. Moreover, the substantial influence of fiber-matrix adhesion on the thermal and dynamic mechanical attributes of treated composites underscores its pivotal role. In summation, the efficacy of DF surface treatment in enhancing the thermal and dynamic mechanical properties of DF fiber rPVC-SAN composites underscores their potential utility, particularly in applications requiring resilience to elevated temperatures.

Footnotes

Declaration of Conflicting Interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Samira Maou

Yazid Meftah

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Thermal and viscoelastic behaviors of recycled polyvinyl chloride/styrene-acrylonitrile blend composites incorporating treated date palm fibers

Abstract

Keywords

Introduction

Experimental

Materials

Extraction Technique of DFs

Surface Modification of DFs

Alkalization of DFs

Silanization of DFs

Combination Alkali/Silane Treatment for DFs

Fabrication of the rPVC-SAN-DF Composites

Characterization of Composite

Thermal Analysis

Dynamic Mechanical Analysis (DMA)

Results and Discussion

TGA of rPVC-SAN-DF Composites

DTG Results of rPVC-SAN-DF Composites

DSC of the rPVC-SAN-DF Composites

Viscoelastic Results of rPVC-SAN-DF Composites

Storage Modulus

Loss Modulus (LM)

Damping Factor (Tan δ)

Cole–Cole Plots

Conclusions

Footnotes

Declaration of Conflicting Interests

Funding

ORCID iDs

References