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A well-defined poly(e-caprolactone) (PCL) with terminal azido group was prepared. Grafting-on reaction between the azido-terminated PCL (N 3 APCL) and ultrasonication-assisted exfoliated graphene flakes (GF) was carried out to obtain PCL-grafted-GF (PCL-g-GF) which showed good dispersibility in a wide variety of organic solvents. Gel permeation chromatography, 1 H NMR, IR, Raman, UV-vis, and TEM measurements indicated that PCL macromolecules were covalently introduced on the surface of GF without disrupting the structure of GF.

Pour point depressants (PPDs) commonly used in the oil and gas industry as a chemical wax inhibitor to control the temperature of the crude oil below their wax appearance temperature (WAT) points, and to improve the flowability of crude oil. In this study, different conditions of Stearyl Acrylate-Behenyl Acrylate (SABA) copolymer were synthesized by free-radical solution polymerization method at different range conditions of polymerization. Four factors considered during the synthesize of the copolymer are the mass ratio of monomers (1:1, 1:2, 1:3, 2:1, and 3:1 wt%), reaction temperature from 60 to 100 °C, the concentration of initiator from 0.5 to 2.5 wt% and reaction time from 5 to 9 hour. The results showed that the best conditions to obtain the highest yield of SABA copolymer were at the mass ratio of monomers of 1:1 (w/w), the reaction temperature of 90 °C, the reaction time of 7 h, and concentration of initiator at 1 wt%.

In recent years, polymeric additives have received considerable attention as a wax control approach to enhance the flowability of waxy crude oil. Furthermore, the satisfactory model for predicting maximum yield in free radical polymerisation has been challenging due to the complexity and rigours of classic kinetic models. This study investigated the influence of operating parameters on a novel synthesised polymer used as a wax deposition inhibitor in a crude oil pipeline. Response surface methodology (RSM) was used to develop a polynomial regression model and investigate the effect of reaction temperature, reaction time, and initiator concentration on the polymerisation yield of behenyl acrylate-co-stearyl methacrylate-co-maleic anhydride (BA-co-SMA-co-MA) polymer by using central composite design (CCD) approach. The modelled optimisation conditions were reaction time of 8.1 h, reaction temperature of 102 °C, and initiator concentration of 1.57 wt%, with the corresponding yield of 93.75%. The regression model analysis (ANOVA) detected an R2 value of 0.9696, indicating that the model can clarify 96.96% of the variation in data variation and does not clarify only 3% of the total differences. Three experimental validation runs were carried out using the optimal conditions, and the highest average yield is 93.20%. An error of about 0.55% was observed compared with the expected value. Therefore, the proposed model is reliable and can predict yield response accurately. Furthermore, the regression model is highly significant, indicating a strong agreement between the expected and experimental values of BA-co-SMA-co-MA yield. Consequently, this study’s findings can help provide a robust model for predicting maximum polymerisation yield to reduce the cost and processing time associated with the polymerisation process.

Wax deposition in production pipelines and transportation tubing from offshore to onshore is critical in the petroleum industry due to low-temperature conditions. The most significant popular approach to solve this issue is by inserting a wax inhibitor into the channel. This research aims to reduce the amount of wax formation of Malaysian crude oil by estimating the effective parameters using Design-Expert by full factorial design (FFD) method. Five parameters have been investigated, which are rotation speed (A), cold finger temperature (B), duration of experimental (C), the concentration of poly (stearyl acrylate-co-behenyl acrylate) (SABA) (D), and concentration of nano-silica SiO2 (E). The optimum conditions for reducing the amount of wax deposit have been identified using FFD at 300 rpm, 10 ℃, 1 h, 1200 ppm and 400 ppm, respectively. The amount of wax deposit estimated is 0.12 g. The regression model’s variance results revealed that the R2 value of 0.9876, showing 98.76% of the data variation, can be described by the model. The lack of fit is not important in comparison to the pure error, which is good. The lack of fit F value of 12.85 means that there is only a 7.41% probability that this huge can occur because of noise. The influence of cold finger temperature was reported as the main contributing factor in the formation of wax deposits compared to other factors. In addition, the interaction between factor B and factor C revealed the highest interaction effect on the wax deposition. In conclusion, the best interaction variables for wax inhibition can be determined using FFD. It is a valued tool to measure and detect the unique relations of two or more variables. As a result, the findings of this study can be used to develop a reliable model for predicting optimum conditions for reducing wax deposits and the associated costs and processing time.