1. Introduction
Sustainability is defined as “meeting the needs of the present generation without compromising the ability of future generations to meet their own needs” [
1]. Sustainability focuses on the “triple bottom line” (3BL), which comprises social, economic, and environmental dimensions. Social sustainability means a commitment to providing everyone access to healthcare, education, food, water, and shelter. It also means maintaining a stable and peaceful global community of nations. Economic sustainability means being prepared for economic recessions, investing money with a long-term view, regulating the financial industry, and reducing the national debt. Environmental sustainability is about climate change, global warming, human coexistence, ocean acidification, ecosystem collapse, air pollution, and ozone depletion. Solutions in this dimension include renewable energy, protecting endangered species, reducing emissions, and recycling. With a commitment to the sustainability dimensions in all industries and activities, the world can make a big transition to an exciting and thriving future.
There is a conflict between the sustainability concept and the aims of the plastic and petrochemical industries. For instance, the plastic and petrochemical industries play a pivotal role in economic growth and contribute significantly to the GDP of many countries. However, the operations of these industries negatively and diversely impact environmental aspects, which lead to resource depletion, high GHG emissions, and global warming. All these issues endanger the social and environmental dimensions of sustainability [
2]. In fact, plastic and petrochemical industries are responsible for consuming a large amount of energy, releasing GHG emissions to the atmosphere, generating wastewater and hazardous wastes, and releasing toxic gases [
3]. Additionally, plastic and petrochemical facilities use non-renewable feedstock and store a large amount of flammable and toxic materials, which may pose a high risk to the surrounding population, assets, and environment [
4]. In fact, a large fraction of plastics ends up in landfills, and ultimately, in the environment; only 9% of all the plastic has been recycled [
5]. Most plastics do not degrade, and some plastics, after being discarded, stay in the environment for a long time because their decomposition rates are very low. Serious incidents in plastic and petrochemical industries have been reported, including chemical spills, chemical fires, and explosions, which caused deaths, injuries, and major damage to assets. Hazards associated with petrochemical industries include air pollutants, groundwater and surface water contamination as well as soil contamination, acid rain, ozone layer depletion, etc. Ideally, these types of pollution should compel these industries to exert massive efforts to balance their operational and financial performance in order to ultimately improve their sustainability performance. New promising technologies such as Industry 4.0 technologies, lean manufacturing, machine learning, and the circular economy have been created and are practiced nowadays to help the world foster sustainability. Moreover, these technologies are capable of confronting and withstanding problems and difficulties faced by the plastic, petrochemical, and other industries. Lean manufacturing principles are now being used widely by many industries, and these tools have been recognized in different countries as successful operational frameworks for reducing waste, increasing productivity, and continuous improvement [
6,
7,
8]. Lean manufacturing is “a set of management principles and techniques geared towards eliminating waste in the manufacturing process and increasing the flow of activities that, from the customers’ perspective, add value to the product” [
9,
10]. Many researchers have studied the linkage between sustainability and lean manufacturing practices in different industries, including pharmaceutical, automotive, leather, etc. Lean manufacturing helps in minimizing waste and costs, thereby improving productivity and increasing profits [
11]. It has been proven that lean manufacturing principles are essential for any organization to achieve sustainability goals [
12,
13]. In the environmental aspect, the role of lean manufacturing in improving the quality of products and minimizing stored materials has led to the decrease of pollutant levels and the slowing down of resources depletion [
14]. Value stream mapping is a lean manufacturing tool that helps to map raw materials, energy, and water, thereby minimizing waste and contributing to the protection of the environmental [
15]. With regard to the economic aspect, lean manufacturing provides tools that contribute to minimizing waste, thereby increasing market share and profits [
16]. From a social perspective, lean manufacturing contributes to minimizing waste and improving occupational health and safety, thus improving the living conditions of society [
17,
18]. Several studies have been conducted to examine the impact of lean manufacturing on sustainability performance. For instance, Iranmanesh et al. [
19] studied the impact of lean manufacturing practices on the sustainability performance of different industries, including plastic. Their findings support the hypothesis that lean manufacturing practices positively influence sustainability, with the existence of lean culture as a moderator. Similarly, ref.[
20] considered the impact of lean manufacturing implementation on organizational performance across various industries in Zimbabwe. Garza-Reyes et al. [
21] studied the quality practices of European pharmaceutical companies to explore how ready they were to implement lean manufacturing. A survey questionnaire was prepared and given to 310 European pharmaceutical companies. The findings of this study showed that the participating companies’ lean readiness was insufficient. Simultaneously, it was determined that factors such as ISO 9000 certification, type of supplier relationships, and company size had no impact on the quality practices of European pharmaceutical manufacturing organizations, and thus on their level of lean readiness.
The competition to acquire more market shares has put pressure on organizations to upgrade their current manufacturing operations and practices to more advanced levels by exploiting the emerging technologies of Industry 4.0. The new manufacturing systems are now smarter, more intelligent, flexible, digital, agile, and well-equipped to confront market volatility and keep up with the evolution of international markets [
22,
23]. Global manufacturing industries have seen a huge change with the advent of Industry 4.0 technologies such as cloud computing, big data analysis, robotic systems, and the Internet of Things. Industry 4.0 technologies play a critical role in manufacturing industries and their sustainability performance, bringing about enhanced machineries, improved communication technology, reduced lead times, improved working environments, and product quality [
24,
25].
Industry 4.0 technologies are expected to significantly improve the three dimensions of sustainability performance of any organization. In the economic dimension, Industry 4.0 technologies positively enhance manufacturing flexibility and the quality of products. The digitalization features of Industry 4.0 technologies contribute to low production time, reduces lead time, minimizes production and transportation costs, which then lead to high customer satisfaction, ultimately increasing the organization’s market share and profits [
26,
27]. Regarding the environmental aspect, the availability of real-time data and data sharing between supply chain stakeholders contribute to the allocation of raw materials, water, energy, and workforce time effectively [
27,
28], which help to minimize resource depletion, GHG emissions, and waste generation [
29]. From the social perspective, implementing Industry 4.0 technologies in organizations improves work conditions, provides safe working conditions for workers, and offers new technologies for people, thereby enhancing motivation and morale [
24,
30].
Taken together, Industry 4.0 technologies and lean manufacturing are significantly improving the sustainability of organizations. Moreover, their combination helps to reduce waste and cost in areas where it is impossible to use only lean manufacturing. Additionally, the integration of Industry 4.0 technologies and lean manufacturing contributes to the reduction of the implementation costs of Industry 4.0 technologies as it is more costly to implement them without advancing in lean manufacturing principles [
31]. Few studies have addressed the relationship between the two in different manufacturing industries [
32,
33,
34]. Lean manufacturing offers new innovative and automation technologies for organizations [
31]. The integration of Industry 4.0 technologies with lean manufacturing helps to remove or minimize some barriers that hinder the implementation of lean manufacturing [
32]. The availability of real-time data provided by digitalization and Industry 4.0 technologies is useful for analyzing the current problems with the use of value stream mapping [
35]. Nara et al. [
36] studied the impact of Industry 4.0 technologies on the sustainability of the plastic industry in Brazil. The study outcome revealed that the IoT, sensors, and big data would enhance the sustainability of the plastic industry.
The literature indicates that there is a lack of research on the integrated impact of Industry 4.0 technologies and lean manufacturing principles on the sustainability performance of organizations. To the best of our knowledge, there is only one study that investigated the relationship between lean manufacturing, Industry 4.0, and the sustainability performance of Indian manufacturing organizations. The scarcity of information regarding this relationship despite the unfavorable and negative impacts of the plastic and petrochemical industries on sustainability performance only exposes the need for further research in this area.
In this regard, the novelty of this study is its exploration of the casual relationship between Industry 4.0 and sustainability performance, between lean manufacturing and Industry 4.0, and the joint impact of Industry 4.0 technologies and lean manufacturing on the sustainability performance of the plastic and petrochemical industries in Saudi Arabia. Additionally, the paper ascertains whether lean manufacturing has a mediating impact on the relationship between Industry 4.0 and sustainability performance. This study offers a new insight into the impact of Industry 4.0 technologies and lean manufacturing on the environmental, economic, and social performance of the plastic and petrochemical industries. In addition, it highlights managerial implications and theoretical contributions to the selected industries. Although Saudi Arabia is one of the world’s largest producers of petrochemicals and plastics, many of the enterprises are still implementing Industry 3.0 and have not yet adopted Industry 4.0 technologies extensively. Furthermore, there is a lack of research on these two areas within Saudi Arabian organizations. Thus, this study can assist decision makers in moving towards the adoption of Industry 4.0 and lean manufacturing, similar to their counterparts in other countries. Likewise, the study findings could serve as a foundation of knowledge for decision makers and enterprise managers as they build strategies and policies that will allow their organizations to excel in Industry 4.0 technologies and lean manufacturing. Most of the previous studies surveyed experts from different industries, which might have given inaccurate results. Comparatively, this study is carried out on specific industries, which will create a more generalized understanding of the relationship between Industry 4.0, lean manufacturing, and sustainability performance.
To achieve the study aims, a conceptual framework is developed and a set of hypotheses based on literature review is established. Then, the required data collected from 112 Saudi plastic and petrochemical industries are analyzed using structural equation modeling (SEM) in order to validate the suggested model empirically. Finally, theoretical contributions and managerial implications are highlighted and drawn from the obtained results.
The remaining parts are organized as follows.
Section 2 provides a background on lean manufacturing, Industry 4.0 technologies, and sustainability performance.
Section 3 provides the proposed hypothesis and framework.
Section 4 provides the materials and methods used to conduct this research.
Section 5 analyzes the results of this study. The main findings are discussed in
Section 6.
Section 7 concludes the work and provides directions for further research.
6. Discussion
Plastic and petrochemical industries play a significant role in economic growth, minimize unemployment, and enhance living conditions in Saudi Arabia. However, plastic and petrochemical industries are lagging behind in their environmental and social sustainability performance, which has put a huge burden on society and the environment. New emerging technologies such as Industry 4.0 and lean manufacturing practices have gained increasing attention from researchers and industries in major economies, which has helped the plastic and petrochemical companies to confront and mitigate the abovementioned issues.
This paper investigated the direct impact of Industry 4.0 technologies and lean manufacturing on sustainability performance, and the integrated impact of Industry 4.0 technologies and lean manufacturing on the sustainability performance of plastic and petrochemical industries in Saudi Arabia. Moreover, it analyzed the mediating impact of lean manufacturing on the relation between Industry 4.0 technologies and sustainability performance. This study indicated that plastic and petrochemical industries in Saudi Arabia are on the verge of implementing Industry 4.0 technologies, and revealed that Industry 4.0 technologies directly and positively influence sustainability performance (H1), confirming that Industry 4.0 technology can have a substantial impact on the sustainability performance measures in Saudi plastic and petrochemical industries. The findings are consistent with previous studies that claimed the existence of a relationship between Industry 4.0 and sustainability performance [
24,
92,
93]. The findings indicated that Industry 4.0 technologies have attracted the interest of Saudi Arabia’s plastic and petrochemical industries as a practical solution for improving organizational performance. It can be concluded that the Internet of Things was given the highest priority among all technologies in Industry 4.0, followed by big data analysis and cloud computing. However, robotic systems, augmented reality, and additive manufacturing were given less priority for sustainability performance. Many of the industries in Saudi Arabia, especially the small and medium enterprises, are still implementing Industry 3.0 and have not adopted Industry 4.0 technologies. The digitalization feature of Industry 4.0 technologies will contribute to lower plastic and petrochemical production time, reduce lead time, minimize production and transportation costs, leading to high customer satisfaction and ultimately increasing the organizations’ market share. The availability of real-time information would help to allocate resources efficiently, which would minimize resource depletion, the GHG emissions, and reduce plastic waste generation.
This study found that the impact of Industry 4.0 technologies on sustainability performance is magnified with the presence of lean manufacturing as a mediating variable. This implies that adopting Industry 4.0 technologies without lean manufacturing may not have a noticeable and swift impact on sustainability performance since lean manufacturing concentrates on developing the human aspect, which has a substantial influence and drives organizational sustainability [
13]. The findings of this paper encourage the plastic and petrochemical industries to adopt Industry 4.0 technologies in order to enhance their sustainability performance, with lean manufacturing as part of the organizations’ core process strategy. Jointly, Industry 4.0 technologies and lean manufacturing are expected to help plastic and petrochemical companies to reduce waste and costs in areas where it is impossible to use either lean manufacturing or Industry 4.0 technologies solely. For instance, the effectiveness of suppliers’ feedback and just-in-time on enhancing the sustainability of the plastic and petrochemical industries can be improved significantly through the use of big data, sensors, and Internet of Things [
94,
95,
96]. Both Industry 4.0 and lean manufacturing concentrate on leading industries towards a linked and data-driven environment in which manufacturing systems and supply chains can be improved through real-time and customer-oriented integration. Industry 4.0 technologies and lean manufacturing provide advanced instrumentation technologies, adjustable big data analytics for process optimization, advanced hardware and software platforms, and predictive modeling and simulation technologies.
Similarly, the findings of this paper indicate that Industry 4.0 technologies directly and positively enhance lean manufacturing practices (H2). This is in line with previous studies that claimed the direct and positive impact of lean manufacturing and Industry 4.0 technologies [
14,
97,
98,
99]. This paper further confirms that claim in Saudi Arabia’s plastic and petrochemical industries. Moreover, these research findings are more important and relevant than the previous works because Industry 4.0 technologies and lean manufacturing were shown to have a positive and greater association with the enhancement of the environmental dimension of sustainability performance, which is relevant to the plastic and petrochemical industries. These findings imply that the respondents perceive the joint and the significant impact of Industry 4.0 and lean manufacturing on the environment. This means that adopting lean manufacturing and Industry 4.0 technologies in the plastic and petrochemical industries would significantly protect environment. In addition, it demonstrates the statistical significance of all Industry 4.0 technologies and lean manufacturing principles, implying that Saudi Arabian industries acknowledge and recognize the contribution of these principles and tools to the enhancement of sustainability performance, which implies that adopting Industry 4.0 technologies in the presence of lean manufacturing helps to upgrade lean manufacturing to digital lean manufacturing, allowing material and information sharing among all supply chain parties [
32]. Moreover, Industry 4.0 technologies can enhance the customer involvement, which would bring the voice of the customer to the early stages of production [
100].
In conclusion, lean manufacturing was found to be a substantial mediating variable that is required for the successful implementation of Industry 4.0 technologies. Moreover, the paper introduced a list of valid constructs for Industry 4.0 technologies, lean manufacturing, and sustainability performance from the perspectives of the plastic and petrochemical industries in Saudi Arabia. These constructs and the model were tested for convergence and divergence validity.
7. Conclusions
The study values the role of Industry 4.0 technologies and lean manufacturing as powerful tools for advancement in achieving sustainably in the plastic and petrochemical sectors. This study primarily focused on investigating the direct impact of Industry 4.0 technologies and lean manufacturing on sustainability performance, and the integrated impact of Industry 4.0 technologies and lean manufacturing on the sustainability performance of plastic and petrochemical industries in Saudi Arabia. The results revealed a solid relationship between Industry 4.0 technologies and sustainability performance, and confirmed the casual relationship between lean manufacturing and Industry 4.0 technologies. Moreover, this relationship is strengthened with the presence of lean manufacturing as a mediating variable. Thus, organizations should be committed to adopting Industry 4.0 technologies in order to make the manufacturing process digital, lean, and smart.
These findings could provide decision makers in the plastic and petrochemical industries with the means and insights into the importance and necessity of adopting both Industry 4.0 technologies and lean manufacturing in their organizations, which will jointly enhance sustainability performance. Moreover, the study findings will serve as a foundation of knowledge for decision makers and enterprise managers as they build strategies and policies to excel in Industry 4.0 technologies and lean manufacturing. In addition, the study outcome introduces a list of valid constructs for Industry 4.0 technologies, lean manufacturing, and sustainability performance from the perspectives of the plastic and petrochemical industries in Saudi Arabia. These construct will provide support to the decision makers in adopting Industry 4.0 technologies and lean manufacturing by convincing the supply chain stakeholders. Additionally, the research output provides a roadmap to practitioners and stakeholders by highlighting the relevance of Industry 4.0 technologies and lean manufacturing to the economic, social, and environmental success of their organizations. The research outcomes also show that Industry 4.0 technologies have attracted the interest of Saudi Arabia’s plastic and petrochemical industries. It is revealed that the Internet of Things scored the highest among other technologies, followed by big data analysis and cloud computing. On the other hand, robotic system, augmented reality, and additive manufacturing were given less priority in sustainability performance.
Some assumptions made in this research need to be further considered in future research. For example, Industry 4.0 technology is relatively new to Saudi Arabian industries, so the respondents’ knowledge on Industry 4.0 is limited. Thus, the answers of the respondents to this part might not be based on their expertise in this field. Therefore, it is recommended to further explore the maturity, awareness, drivers, and challenges of Industry 4.0 technologies in Saudi Arabia. Moreover, as the majority of the industries have not yet implemented both Industry 4.0 technologies and lean manufacturing, the views expressed by the respondents might not be accurate. We therefore recommended to examine the level of integration of both technologies in Saudi Arabian industries. This study is limited to the petrochemical and plastic industries in Saudi Arabia and can be extended to other gulf countries. It can also be implemented in different industries such as small and medium manufacturing enterprises, automobile, oil, leather, etc. Another direction is addressing a large sample size. This study can additionally be extended to different dimensions, for instance, the study of the impacts of other mediating variables such as the circular economy.