1 Introduction

Since the invention of the first mechanical device, there has been a continuous pursuit of new machinery and advanced technologies. Lubrication is crucial for the design and improvement of such equipment [1, 2]. Lubrication technology has continuously evolved to meet the demands of new applications and mechanical systems. Lubricants, whether they be solid, liquid, or gas, are used at the boundary where two surfaces interact to optimize the effectiveness of machines [3]. Failure to adhere to proper lubrication practices can result in abundant wear and the potential for perpetual damage to equipment. The primary components of lubricants are base fluids, but they often have certain limitations in terms of performance. To overcome these limitations, specialty chemicals known as additives are blended with base fluids [4,5,6]. These additives include corrosion inhibitors, detergents, viscosity modifiers (VM), cold flow improvers (FI), extreme pressure agents, antioxidants, and more. Additives serve multiple purposes and recent research has focused on developing multifunctional additives [7, 8]. FIs and VMs are two of the numerous design parameters that are of utmost significance for the superior performance of lubricants. One key requirement of lubricating oil is its ability to remain fluid over a variety of temperatures. The minimum temp. for which the oil begins to flow beneath cold circumstances is indicated by the pour point (PP) [9, 10]. FIs are additives that enhance the fluidity of oil at temperatures below the standard pour point. When temperatures are low as well, paraffinic hydrocarbons existing in the basic fluid tend to separate owing to their poor solubility [11]. Such waxy hydrocarbons attract each other through the forces of Van der Waals, resulting in the crystallization of wax. As the temperature drops further, a solid, interconnecting crystalline structure is produced as the wax crystals expand which causes cold flow issues [12, 13]. FIs hinder wax crystal formation, and inhibit the development of complicated interconnecting networks. Viscosity is another critical property of lubricating fluids [14]. A fluid’s viscosity changes depending on temperature, and it is necessary to maintain a wide variety of lubricant viscosities within the optimal performing conditions of the apparatus being used [15, 16]. When the viscosity is excessively low, the fluid is delicate sufficient to form an adequate lubricant film, leading to increased surface wear and friction. On the other hand, high-viscosity lubricants result in increased fluid friction and decreased energy efficiency [17]. VMs are additives that enhance the quality of viscosity of lubricants and help sustain adequate viscosity across a variety of temperatures. The reliance of the viscosity of lubricant upon temperature is quantified using the Viscosity Index (VI), an empirical variable describing the lubricant’s application temperature range [18, 19]. The Lubricants that have higher VI values exhibit an increase in viscosity resistance to changes regarding temperature variations and are generally prominent in the majority of mechanical systems [14, 20].

Nanotechnology is gaining a huge interest in the oil industry [21]. The utilization of nanotechnology in the development of pour point depressants (PPDs) of crude oil has gained significant attention in recent years [22,23,24]. Nanocomposites, in particular, offer unique advantages and properties that can enhance the performance and efficiency of PPDs [25]. Here are some key aspects of nanotechnology-based PPDs:

Improved Dispersion Nanocomposites facilitate better dispersion and distribution of PPDs in lube oil [26]. By incorporating nanoscale particles or additives, the PPDs can interact more effectively with wax crystals, inhibiting their growth and enhancing the oil’s flow properties at lower temperatures [27].

Increased Surface Area Nanoparticles used in PPDs possess an enormous ratio of surface to volume. This increased surface area allows for enhanced interactions with waxy components in lube oil. The nanoparticles can adsorb onto the wax crystals’ surface, disrupting their expansion and preventing agglomeration, thereby lowering the pour point of the oil [28].

Tailored Properties Nanocomposites can be designed with specific properties to address the challenges associated with wax deposition and flow properties of lube oil. By controlling the size, composition, and surface characteristics of nanoparticles, the performance of PPDs can be optimized for different types of crude oils and operating conditions [29].

Synergistic Effects Defined as the combined effects of at least substances making an impact that is more significant than both of them could have shown by themselves. Nanotechnology-based PPDs can exhibit synergistic effects by combining different nanoparticles or additives. The careful selection and combination of nanomaterials with complementary properties can enhance the overall effectiveness of PPDs, resulting in greater pour point reduction and improved flow properties [30].

Reduced Dosage Requirements Nanocomposite PPDs have shown the potential to reduce the dosage required for effective pour point depression. The improved dispersion and interaction achieved through nanotechnology enable lower concentrations of PPDs to achieve the desired effect, reducing costs and potential environmental impact.

While nanotechnology-based PPDs offer promising benefits, further evaluation is necessary to assess their long-term performance, safety, and environmental impacts. Regulatory considerations and the scalability of nanocomposite production should also be taken into account for widespread adoption. In summary, the application of nanotechnology, particularly nanocomposites, in the development of PPDs for lubricating oil holds great potential for improving the efficiency and a pour point depression’s effectiveness. This advancement may enhance the flow attributes and transportation of the crude oils that are waxy, contributing to the overall efficiency for the oil industry [31].

The purpose of this research was to synthesize copolymers by combining 1-dodecene (DD) or 1-hexadecene (HD) with octadecyl methacrylate (ODMA) through free radical polymerization. Additionally, the researchers aimed to prepare ODMA-DD and ODMA-HD nanocomposites utilizing magnetite nanoparticles (Fe3O4) via emulsion polymerization. These newly synthesized copolymers and their nanocomposites were evaluated for their potential as FIs and PPDs for local lubricating oils. Comparative analysis revealed that a nanocomposite displayed superior performance as a cold flow improver for lubricating oil. The effectiveness of these newly developed flow improvers was validated through measurements of the viscosity index (VI), the pour point temperature (PPT), and the rheological properties (RP). With the necessity to gain a comprehensive knowledge of the chemical and physical properties of the synthesized copolymers and nanocomposites, a range of analytical techniques were employed. These techniques included scanner electron microscope (SEM), X-ray diffraction (XRD), dynamic light scattering (DLS), differential scanning calorimetry (DSC), as well as Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1HNMR). Through these measurements, valuable insights into the morphological as well as structural characteristics of the prepared materials have been obtained. The successful synthesis and characterization of copolymers consisting of 1-dodecene (DD) or 1-hexadecene (HD) with octadecyl methacrylate (ODMA), (CP1 and CP2 respectively), as well as their nanocomposites (NP1 and NP2), were achieved. Notably, the nanocomposites demonstrated enhanced performance as flow improvers for lubricating oil. The properties of these materials were thoroughly investigated using various analytical techniques, contributing to the manufacturing of innovative compounds for the improvement of the flow properties of lubricating oils.

The innovation in this work lies in the synthesis of a novel pour point depressant using a polymeric nanocomposite. By incorporating magnetite nanoparticles into the polymethacrylate matrix, the researchers aimed to enhance the performance of the pour point depressant. This approach represents a new and unique solution for addressing the challenges associated with waxy crude oil.

Additionally, the study innovatively assessed and compared the efficacy of the synthesized pour point depressant and the individual polymers in reducing various properties of the crude oil, including gelation point, yield stress, apparent viscosity, and pour point. The extensive assessments conducted using rheometry tests and various characterization techniques demonstrate a comprehensive and innovative approach to evaluating the performance and mechanisms of action of the additives.

2 Materials and methods

2.1 Materials

The chemicals utilized for this investigation were sourced from reputable vendors. Methacrylic acid (99%), Stearyl alcohol (> 99), 1-dodecene, 1-hexadecene, benzoyl peroxide (initiator), p-toluenesulfonic acid (P-TSA), sodium salt of dioctyl-sulfosuccinate (surfactant), and hydroquinone were obtained via Sigma Aldrich Chemical Company. Iron (II) sulfate heptahydrate (> 99%), potassium hydroxide (99.9%), and potassium nitrate are all sourced by Merck Specialties Private Limited. The solvents used in the experiment that containing xylene, hexane, methanol, toluene, and sodium carbonate, were provided by Edwic Co. All substances used in the study were of scientific quality, except for benzoyl peroxide, which was of chemical quality. The lubricating oil used in the experiment was obtained from a reputable Co-operation Company in Egypt.

2.2 Octadecyl methacrylate synthesis

In order to synthesize octadecyl methacrylate (ODMA), an esterification reaction was carried out in a molar ratio of 1:1 of stearyl alcohol and methacrylic acid. The reaction was conducted whenever there is toluene, hydroquinone, and p-PTSA (para-toluenesulfonic acid), using a flask with three necks possessing a Dean-Stark device and condenser [32, 33]. The Dean-Stark apparatus was employed to collect the water generated during the reaction process. The reaction mixture’s heat was elevated incrementally to a maximum of 110 °C from the ambient temperature. By observing the total volume of water collected in the Dean-Stark apparatus, the progression of the reaction could be evaluated. To obtain the desired product, the resultant ester, stearyl methacrylate, underwent multiple washes using a 5% Na2CO3 solution until the solution achieved clarity. Subsequently, it was washed by distilled water and subjected to vacuum drying. Reaction process is presented in the Scheme 1.

Scheme 1
scheme 1

Chemical reaction for synthesizing esters and their copolymers (CPs)

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2.3 Copolymers synthesis

Reaction of polymerization involved a combination of 1-dodecene (DD) or 1-hexadecene (HD) and octadecyl methacrylate (ODMA) in a 1:1 molar ratio to produce ODMA-DD polymer and ODMA-HD polymer, respectively. The reaction mixture also included an initiator and toluene. The reaction was performed at a temperature of 95 °C over 6 h. For stopping the reaction, the mixture was dropped onto methanol while stirring, causing a precipitate to form as a result. A copolymer was then repeatedly precipitated from a solution of hexane using methanol, and then dry it at 70 °C under vacuum. A reaction process is shown through Scheme 1.

2.4 Magnetite nanoparticles synthesis

The process explained by Bruce et al. [34] was used for synthesizing magnetite nanoparticles. A solution of Iron (II) sulfate heptahydrate, potassium hydroxide, and potassium nitrate solution was prepared. To the iron salt solution, surfactant (CTAB) was introduced at a rate of 1% (w/w) and stirred vigorously for 2 h. Then potassium nitrate was introduced and the mixture was agitated for another 30 min. Slowly adding a potassium hydroxide solution, the reaction solution was heated till 100 °C for two hours in an atmosphere of nitrogen. After cooling, a black precipitate had been washed, centrifuged, and finally dried under a vacuum.

2.5 Synthesis of polymeric nanocomposites

To prepare the polymer-Fe3O4 nanocomposites, the polymer/toluene solution was blended with nano-Fe3O4 particles. The suspension had been prepared by dissolving 5 from polymer to toluene with adding a desired quantity of nano-Fe3O4 particles (0.5, 1, or 1.5 mg) under an ultrasonic wave that is vigorously stirring. On a glass surface, the suspension was subsequently poured and allowed to naturally evaporate the toluene, resulting polymer-nano-composites mass that is semisolid. The acquired material had been subsequently characterized. The reaction is demonstrated in the Scheme 2.

Scheme 2
scheme 2

The reactions involved in synthesizing copolymers and their nanocomposites (NPs)

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2.6 Measurements

To obtain Fourier Transform Infrared Spectrometer (FT-IR) spectra, potassium bromide (KBr) was used to analyze the synthezied polymers and their nanocomposites in the 4000–400 cm−1 wavenumber spectrum. FT-IR (USA) was employed for this purpose.

The synthesized polymers’ chemical composition and their nanocomposites were identified via 1HNMR, it is a technique with the Avance III Switzerland-based 500 MHz frequency instrument. Tetramethylsilane was utilized as an internal standard, and deuterated chloroform was provided as the solvent [35].

The dynamic light scattering (DLS) was performed using a Brookhaven + 90 model (USA) equipped with a size/zeta potential analyzer to determine the particle sizes.

The NPs’ magnetic characterization: utilizing a vibrating sample magnetometer (VSM) at 300 K with a magnetic field ranging from 10 kOe to + 10 kOe, the NPs’ magnetic properties were determined [36].

X-ray diffraction (XRD, Advance D8, Bruker) and the Field Emission Scanning Electron Microscope (FE-SEM) were used to characterize the nanoparticles and their composites.

The SHI-MADZU DTG-60 thermo gravimetric analyzer (Japan) was used to carry out TGA and differential scanning calorimetry experiments to examine the produced copolymers’ thermal stability. The analysis was conducted in an alumina crucible in air, with a 10 °C/min rate of heating and a 0 to 550 °C for a testing range of temperature.

Gel Permeation Chromatography (GPC) method using the HLC-8320 instrument was used for determining the molecular weights as well as polydispersity of the polymers.

A Lecia DM4 polarised microscope (Germany) was used to analyze the wax crystal structure of lubricating oil samples. Pictures have been captured at approximately 0 °C with a magnification of 100x.

The pour points of lubricating oils that had been treated and those that hadn’t were determined utilizing ASTM D-97 Standard technique [37, 38].

The rheological properties of the lubricating oils were investigated by utilizing an Anton-Paar MCR302 rheometer at various temperatures (0, 15, 25, and 35 °C) and with a shear rate of 5 s−1.

Viscosity indices of the lubricating base oil, prior to and following treatments with additives at 10,000 ppm, were calculated following the ASTM D2270 standard procedure. At 40 °C and 100 °C, the kinematic viscosities were determined for this purpose [38, 39].

3 A discussion of the results

3.1 FTIR evaluation

The FTIR spectra of CP1, CP2, NP1, and NP2 were exhibited within Fig. 1.The obtained peaks in the spectra are as follows: 2922 cm−1 and 2917 cm−1 are observed concerning the stretching vibration for paraffinic C–H bonds in the –CH2– groups, 1734.56 cm−1 is attributed to C=O bonds and 1207 and 1335 cm−1 are attributed to C–C and C–O bonds. Notably, no notable peaks were identified in the range of olefinic bonds at 1639 cm−1, which further supports the formation of the polymer. However, in the charts of the nanocomposites, additional peaks were observed. Specifically, a peak at 1152 cm−1 can be attributed to Si–O–Si bonding, with SiO2 having a peak at 625 cm−1, confirming the composition of the polymer nanocomposites. For polymer/Fe3O4 nanocomposite, absorption was observed for the ester carbonyl group at 1726.12 cm−1. This change in the frequency of carbonyl stretching could be caused by an interaction between nano magnetite and poly methacrylates [40].

Fig. 1
figure 1

a FT-IR of copolymer CP1, b FT-IR of copolymer CP2, c FT-IR of copolymer NP1, and d FT-IR of copolymer NP2

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3.2 The 1H NMR spectrum of the CPs as well as their NPs

The copolymers’ and their nanocomposites’ 1HNMR spectra are displayed in Fig. 2. CH3, CH2, and CH, respectively, are responsible for the resonances at 0.878 ppm, 1.21 ppm, and 1.47 ppm. The resonance within the 1.96–2.37 ppm range is attributed to COCH, while the peak at 3.61 ppm corresponds to COCH2. Additionally, a peak in the range of 4.013–4.23 ppm is attributed to OCH. In the NMR, there is no singlet signal between 5 and 6 ppm spectrum evidence indicates there are no vinylic protons present in the polymers. In this case, the absence of vinylic protons suggests that the polymer does not contain any vinyl groups or unsaturated bonds in its structure [41, 42].

Fig. 2
figure 2

a 1HNMR of CP1, b 1HNMR of CP2, c 1HNMR of NP1, and d 1HNMR of NP2

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3.3 TGA and DSC analysis

Thermal gravimetric analysis was used to study the heat behavior concerning the copolymers and their nanocomposite and was demonstrated in Fig. 3. Nano-Fe3O4 has been incorporated into prepared polymers to enhance the composites’ thermal stability. Degradation percentages for CP1, CP2, NP1, and NP2 at 380 °C were measured to be 32.42%, 21.35%, 20.64%, and 20.1%, respectively. Similarly, the percentages of loss of weight around 490 °C for CP1, CP2, NP1, and NP2 were found to be 93.71%, 69.56%, 69.12%, and 68.12%, respectively. The addition of nano-Fe3O4 effectively inhibited the degradation of the polymer, resulting in improved thermal stabilities of the polymer composites. These enhancements can be attributed to the reduction in the movement of the chain of polymers and the ability that magnetite nanoparticles to scavenge free radicals, which are crucial factors in enhancing the thermal stability of the composites [43, 44].

Fig. 3
figure 3

TGA data of polymer/Fe3O4 nanocomposites

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Applying a technique known as (DSC), allows us to determine whether a compound undergoes endothermic or exothermic reactions by measuring the transformation temperatures and enthalpy changes as a function of temperature [45]. In this study, we used DSC to analyze the nanocomposite of the produced polymers. The DSC curves, illustrated in Fig. 4, revealed that between 75 and 500 °C, there are multiple endothermic peaks, which represent the polymers’ melting and degrading temperatures. Interestingly, an addition of nanoparticles to the polymers increased their thermal stability. This results from the interaction of the polymer particles with the magnetite nanoparticles, which coagulated on the polymer surface [46].

Fig. 4
figure 4

DSC investigation of two distinct polymers and their nanocomposites

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3.4 X-ray diffraction

For the magnetite nanoparticles, we examined their (XRD) pattern. This pattern, taken in 20°–70° (2θ) range, exhibited six distinct peaks at 30.3°, 35.6°, 43.2°, 53.6°, 57.1°, and 62.8° are shown in Fig. 5. These peaks closely matched the patterns reported for magnetite nanoparticles in previous studies [47], confirming the purity of our sample. Notably, there were no peaks corresponding to various shapes of iron oxides such like maghemite or hematite.

Fig. 5
figure 5

Synthesized nano-Fe3O4 XRD pattern

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3.5 DLS, VSM, and SEM analysis

A technique known as dynamic light scattering (DLS) has been employed to analyze how the particles are sized in polymer nanocomposites [48]. In this study, the DLS results Fig. 6a and b showed particle sizes of 78 nm and 82 nm for NP1 and NP2, correspondingly, showing that a successful nanocomposite was produced.

Fig. 6
figure 6

a DLS photos of NP1 and b DLS photos of NP2

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The magnetite nanoparticles’s morphology and the composite were inspecte utilizing scanning electron microscopy (SEM) [49]. Based on SEM pictures illustrated in Fig. 7a and b it is evident that the particles exhibited a nearly spherical shape with a size of average approximately 29 ± 2 nm.

Fig. 7
figure 7

a SEM images of prepared nano-Fe3O4 and b SEM photos of the composite made from nano-Fe3O4 and polymers

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To investigate magnetic behavior of nanoparticles, we employed a 300 K VSM (vibrating sample magnetometer). The magnetization analysis revealed a superparamagnetic behavior, as indicated by the symmetric hysteresis loop with coercivity and remanence values both zero. The magnetization of saturation (Ms) for the magnetic nanoparticles was observed to be 74.25 emu/g. This value is directly relating to the nanoparticles’ size, with larger nanoparticles exhibiting higher saturation magnetization. The higher Ms value observed in our study aligns with the average nanoparticle size determined through SEM analysis [50]. A detailed diagram illustrating the nanoparticles’ magnetic characteristics may be found in a supplementary material. In summary, our study utilized DSC, XRD, SEM, and VSM techniques to characterize the prepared polymers and magnetite nanoparticles. The results revealed that the inclusion of nanoparticles enhanced the polymers’ thermal stability, likely owing to interactions within the polymer particles and the coagulated magnetite nanoparticles. The magnetite nanoparticles exhibited a pure phase with a nearly spherical shape and an average size of approximately 29 nm. Furthermore, they displayed behavior of superparamagnetic when the saturation magnetization value of 74.23 emu/g, which correlated with their size as observed in the SEM analysis [51].

3.6 Evaluation of the CPs and NPs as PPDs

When oil becomes too viscous to flow under the force of gravity, that temperature is identified as the oil pour point. In cold climates, high pour point oils can pose challenges or even prevent the startup of machines [52, 53]. This is because cold oil contains paraffin wax, which tends to crystallize and make the oil harder. To address this issue, pour-point depressants are added to the oil. These additives reduce the ability of the wax to crystallize and lower the pour-point temperature [54]. The presence of waxes in lubricating oils can significantly hinder their storage and functionality. To assess the efficiency of various concentrations of pour-point depressants, pour-point temperatures have been measured and recorded in Table 1. The data was then plotted in Fig. 8. Increasing the dosage of the prepared additives enhances their effectiveness in reducing pour points. For instance, the addition of the depressant caused the pour points of CP1 and CP2 oils to decrease from 0 °C to, respectively, − 18 and − 27 °C. Notably, the most significant decrease was observed when using a polymer nanocomposite treatment. With this treatment, the pour points decreased for NP1 and NP2 from 0 to − 24 °C and − 36 °C, respectively.

Table 1 Pour-point temperatures of lubricating oil that has not been treated (0 °C) and that has been treated with various concentrations of CP1, CP2, NP1, and NP2 and their average
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Fig. 8
figure 8

Relationship between concentration and pour-point temperature

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3.7 Determination of viscosity index

To investigate the efficacy of viscosity-modifying synthetic polymeric additives, the lubricating oil’s viscosity index was determined. Prior to and following the lubricating oil was treated with 10,000 ppm of polymers and composites, the kinematic viscosity of the oil was assessed at 40 and 100 °C [55]. The results are displayed in Table 2. The viscosity index (VI) was raised by adding additives to the lubricating oil. Comparing NPs and CPs revealed that NPs were the most potent flow improver. The VI for the blank sample of lube oil was calculated to be 86.57. Treatment with CP1 or CP2 resulted in VIs of 93.25 and 92.41, respectively. However, treating the oil with NP1 and NP2 increased the VI to 112.34 and 129.36, respectively. These copolymers and their composites show promising potential as flow improvers, particularly NP formulations which yielded superior results.

Table 2 The viscosity index of untreated lube oil and lubricant oil treated with CPs and NPs at a concentration of 10,000 ppm
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3.8 Rheological properties

The presence of numerous different scales in the system, including the diameter of the particles (d), the radius of the polymer chains’ gyration (Rg), and the interactions between the particles and the polymer, is primarily responsible for the rheological behavior [56, 57]. The rheological behavior of lubricating oil that has been treated as well as untreated is assessed by conducting dynamic viscosity measurements at different temperatures [32, 58]. Figures 9 and 10 show the curve of viscosity-shear rate and shear stress versus shear rate curve Figs. 11 and 12 were plotted to analyze the effects. It was observed that as the temperature and shear rate increased, the viscosity decreased. However, when comparing the viscosity of the lubricating oil following the addition of additives relative to the viscosity of the pure lubricating oil, the experimental results revealed a notable increase in viscosity upon the introduction of additives. This is explicable by an increase in shear rate, which decreases waxy aggregates as well as releases the immobilized ongoing phase [59, 60]. The viscosity reduction with increasing shear rate was found to be approximately linear, especially at higher temperatures. The aggregation of wax crystals in lubricating oils is stopped due to the highly polar ester group of oxygen throughout the polymer chain. This polarity induces intermolecular interactions and attractions that hinder wax molecules from aggregating and crystallizing, preserving a more homogeneous and flowing lubricating oil [61, 62]. The Bingham plastic model was used to analyze the experimental shear rate and shear stress observations, where the apparent viscosity is the shear rate’s infinite viscosity. Table 3 provides the conclusions of the apparent viscosity and yield stress derived from the shear stress charts at different temperature levels. The apparent viscosity is a measure of the material’s resistance to flow, whereas the yield stress is a measure of the least amount of force needed to start a flow. These factors are crucial for comprehending the flow behavior and determining out how well the material will withstand deformation and maintain its shape when shear pressures are applied. So it is possible to learn a lot about the rheological characteristics and performance of the material in different applications by analyzing these results. In general, the Bingham model consistently showed that apparent viscosity and yield stress values increased with decreasing temperatures for the samples of lubricating oil that have been both untreated and treated. The treated lube oil with CP1, CP2, NP1, and NP2 exhibited higher values for yield stress and apparent viscosity compared to the pure lube oil. For instance, for CP1, CP2, NP1, and NP2, respectively, the yield stress increased from 651.19 to 816.61, 1075, 1104, and 1424.27, while the apparent viscosity increased from 54.863 cP to 68.31, 118.41, 110.28, and 165.89 cP.

Fig. 9
figure 9

Correlation between apparent viscosity and shear rate for lubricant oils treated with 10,000 ppm from CP1 and NP1 and those that haven’t at temperatures of a 35 °C, b 25 °C, c 15 °C, and d 0 °C

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Fig. 10
figure 10

Correlation between apparent viscosity and shear rate for lubricant oils treated with 10,000 ppm from CP2 and NP2 and those that haven’t at temperatures of a 35 °C, b 25 °C, c 15 °C, and d 0 °C

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Fig. 11
figure 11

Correlation between shear rate and shear stress for lubricant oils treated with 10,000 ppm from CP1 and NP1 and those that haven’t at temperatures of a 35 °C, b 25 °C, c 15 °C, and d 0 °C

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Fig. 12
figure 12

Correlation between shear rate and shear stress for lubricant oils treated with 10,000 ppm from CP and NP2 and those that haven’t at temperatures of a 35 °C, b 25 °C, c 15 °C, and d 0 °C

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Table 3 Shows the values for apparent viscosity and yield stress
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3.9 POM

The impact of temperature on the crystals of lubricating wax, including their size, dispersion, and morphology was investigated using a polarized optical microscope (POM) [63]. Figure 13 presents microscope images of pure oil and samples of treated oil with CP1, CP2, NP1, and NP2 at 0 °C. The image in Fig. 13a shows that the pure lubricating oil wax crystals were larger in size and appeared unorganized. These crystals raised in size rapidly as the temperature decreased. Consequently, the lubricating fluid lost its ability to flow as the crystals stacked on top of each other, forming a 3D network. Figures 13b and c depict the modified shape, quantity, and size of the wax crystals developed in the oil after treatment with CP1 and CP2 at low temperatures. Compared to oil that’s pure, the wax crystals are reduced in size and number. The most significant effect was observed in the lubricating oil treated with NP1 and NP2 (Figs. 13d and e) at low temperatures. In these samples, only a few wax crystals precipitated, and the oil had no difficulty dissolving them.

Fig. 13
figure 13

Pictures captured via a microscope at 0 °C of a Pure oil and oil treated with b CP1, c CP2, d NP1, and e NP2

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4 Conclusions

Researchers focused on preparing ODMA copolymers with α-olefins (HD or DD) using solution polymerization. Following that, they prepared nanocomposites through emulsion polymerization. Synthesized additives were evaluated using various techniques such as FTIR, 1HNMR, DLS, SEM, and thermal analysis (TGA and DSC), which confirmed their high thermal stability. The polymer nanocomposites exhibited well-defined structures at the nanoscale, as evidenced by SEM and DLS images. These additives were found to effectively lower the pour point and raise the cold flow properties of lube oil due to their excellent solubility. Comparing the copolymers and their nanocomposites revealed that the last one yielded superior results in terms of pour point depression (PPD), friction index (FI), and viscosity index (VI). For instance, NP2 exhibited a PPD of − 33 °C and VI of 93.103.

Analysis using polarized optical microscopy (POM) demonstrated that the addition of additives caused modification within the shape as well as size of wax particles in the lubricating oil, resulting in smaller and separated particles. Comparing the performance of the lube oil that has been treated with the copolymers and nanocomposites to commercially available products, concluded that the former exhibited more effectiveness at less cost.

Furthermore, a nanocomposite showed enhanced acting as viscosity modifiers for lube oil. This study highlights the potential of designing multifunctional additives for lubricating oil by incorporating nanoparticles.

Overall, the synthesis of the novel pour point depressant, the comprehensive evaluation of its performance, the exploration of its applications as viscosity index improvers, and the application of advanced characterization techniques collectively represent the innovation in this work. These contributions advance the field of pour point depressants and offer potential solutions for improving the flow properties of waxy crude oil and lubricating oils.