PurposeThis study explores the role of leadership in organisational innovation by reviewing several publications that discuss the relationship between various leadership styles and innovation.Design/methodology/approachThe study followed a descriptive research methodology by reviewing 64 journal articles on the relationship between various leadership styles and innovation. The articles were analysed descriptively and then reviewed based on the leadership style it discusses to derive meaningful findings on the relationship between leadership and innovation.FindingsVarious leadership styles had a positive impact on organisational innovation either directly or indirectly, by influencing the organisational climate, employees' and leaders' behaviours or other organisational variables such as learning and knowledge sharing. Some leadership styles had both direct and indirect impacts on organisational innovation.Research limitations/implicationsThis study collected journal articles published in almost all major electronic databases such as Emerald, ScienceDirect, Taylor & Francis and Scopus. However, the review is limited to journal articles in which the title, abstract or author-specified keywords contain the search terms “leadership” and “innovation,” and published between 2000 and 2019. Therefore, this review may miss some relevant research insights mentioned in the literature that discussed innovation or leadership separately not combined.Originality/valueThis study contributes to the existing body of research on leadership and innovation by extensively discussing the role of various leadership styles in determining organisational innovation. The analysis reveals that prior studies had many limitations and focused on specific leadership styles only. The study goes a step further by explaining how the leadership and innovation aspects are related, and classifying various leadership styles according to their impact on organisational innovation being direct, indirect or both.

Purpose The purpose of this paper is to identify, present and categorise the main requirements, challenges and impacts of Lean Six Sigma (LSS) applications. Emphasis is given to the soft impacts of LSS applications, which are intangible in nature and difficult to quantify and measure, highlighting the most frequently cited ones. Design/methodology/approach A qualitative synthesis of the studies using the narrative synthesis approach is adopted to descriptively summarise and categorise the requirements, challenges and impacts of LSS applications. The studies were searched by using the following keywords: “LSS applications,” “LSS requirements,” “LSS challenges” and “LSS impacts” in almost all major electronic databases such as Emerald, Taylor and Francis, ScienceDirect and Wiley. A total of 116 articles published between 2007 and 2017 in 41 academic journals were collected and reviewed. Consideration was also given to a number of substantial publications in 2006, 2018 and 2019. Findings In addition to its process efficiency and financial impacts, LSS was found to have another impact category related to individual and organisational behaviours. Management commitment, training and organisational culture were concluded to be amongst the most important and required categories for successful LSS applications. It was also found that the lack of awareness of LSS tools and benefits and the lack of change management and resistance to change were amongst the most cited categories of implementation challenges. Research limitations/implications The studies published between 2007 and 2017 are mainly considered in this paper. It is believed that 10-year publication period considered in this research is sufficient to study the evolution, benefits, limitations and future trends of a particular research topic. However, the exclusion criteria used in the search process with respect to the articles’ year of publication and search terms and keywords may limit the generalisation of the research findings. In addition, the qualitative nature of this research study and the lack of empirical data to support its findings is another limitation that future research should consider. Practical implications This research paper may serve as a valuable source of information for LSS researchers as it will provide them with useful and new insights and directions for further research in LSS. It will also increase the awareness of LSS practitioners about the kind of impact LSS has, and therefore, achieve a better utilisation of its tools by ensuring availability of application requirements and overcoming application challenges. Originality/value This study differs from previous research studies as it focusses attention on the soft impacts of LSS applications and highlights them. The study identifies and prioritises LSS application impacts, requirements and challenges. The study on these aspects was found to be limited and lacking in previous research studies.

In this study, synergy between graphene platelets (GnPs) and carbon nanotubes (CNTs) in improving lap shear strength and electrical conductivity of epoxy composite adhesives is demonstrated. Adding two-dimensional GnPs with one-dimensional CNTs into epoxy matrix helped to form global three-dimensional network of both GnPs and CNTs, which provide large contact surface area between the fillers and the matrix. This has been evidenced by comparing the mechanical properties and electrical conductivity of epoxy/GnP, epoxy/CNT, and epoxy/GnP-CNT composites. Scanning electron microscopic images of lap shear fracture surfaces of the composite adhesives showed that GnP-CNT hybrid nanofillers demonstrated better interaction to the epoxy matrix than individual GnP and CNT. The lap shear strength of epoxy/GnP-CNT composite adhesive was 89% higher than that of the neat epoxy adhesive, compared with only 44 and 30% increase in the case of epoxy/GnP and epoxy/CNT composite adhesives, respectively. Electrical percolation threshold of epoxy/GnP-CNT composite adhesive is recorded at 0.41 vol %, which is lower than epoxy/GnP composite adhesive (0.58 vol %) and epoxy/CNT composite adhesive (0.53 vol %), respectively.