In order to reduce the damage to tissue and fill the interstices between fibers, multifilament sutures are frequently treated with certain coating materials. The objective of this study was to create and characterize dopamine hydrochloride (DA) and carboxymethyl chitosan (CMCS) coatings on surgical sutures and investigate their effects on the frictional performance of the surgical sutures during sliding through a skin substitute. The effects of the treatment on the physical and chemical characteristics of the surgical sutures were evaluated. The friction force of the surgical sutures during sliding through the skin substitute was experimentally determined using a penetration friction apparatus. The coefficient of friction (COF) was calculated using a linear elastic model and was used to estimate the frictional behavior of the surgical suture-skin interactions. The results showed that the DA coating could evenly deposit on the surface of the etched multifilament surgical suture surfaces in a weakly alkaline buffer solution. The CMCS coating material could form a uniform film on the surface of the sutures. Minor changes in the surface roughness of the multifilament surgical sutures with different treatments occurred in this study. The friction force and the COF of the multifilament surgical sutures with DA and CMCS coating showed little change when compared with untreated multifilament surgical sutures.

Purpose: The purpose of this paper is to investigate the tribological performance of graphene oxide (GO) sheets as water-based lubricant additive when ultra-high molecular weight polyethylene (UHMWPE) plates slid against 316L stainless steel ball using a reciprocating tribometre. Design/methodology/approach: The factors influencing the tribological performance were considered, including the viscosity of the GO dispersion, normal load, sliding velocity and the roughness of UHMWPE. The surface microstructure and properties of UHMWPE were studied by means of scanning electron microscopy, laser confocal microscopy, Raman spectroscopy and contact angle measurements. Findings: The results revealed that the GO dispersion reduced friction and sliding-wear. The surface images of the wear UHMWPE plates indicated that GO sheets were prone to adsorption on the surface and form a thin physical tribofilms at the substrate. Originality/value: Based on the experimental findings for the evolution of the microstructure morphology and the development of subsurface cracks, less debris and cracking can be observed in the UHMWPE plates lubricated by GO dispersion.

The frictional performances of surgical sutures have been found to play a vital role in their functionality. The purpose of this paper is to understand the frictional performance of multifilament surgical sutures interacting with skin substitute, by means of a penetration friction apparatus (PFA). The influence of the size of the surgical suture was investigated. The relationship between the friction force and normal force was considered, in order to evaluate the friction performance of a surgical suture penetrating a skin substitute. The friction force was measured by PFA. The normal force applied to the surgical suture was estimated based on a Hertzian contact model, a finite element model (FEM), and a uniaxial deformation model (UDM). The results indicated that the penetration friction force increased as the size of the multifilament surgical suture increased. In addition, when the normal force was predicted by UDM, it was found that the ratio between the friction force and normal force decreased as the normal force increased. A comparison of the results suggested that the UDM was appropriate in predicting the frictional behavior of surgical suturing.

Surgical sutures have different sizes, structures, whereas they are being used for various surgeries. The high friction performance of surgical sutures in the suturing process may cause inflammation and pain, leading to a longer recovery time. This paper presents an understanding of the tribological behavior of surgical suture with monofilament and multifilament structures, by means of a penetration friction apparatus (PFA). The results indicated that structure and surface topography of the surgical suture had a pronounced effect on the tribological interactions. It was found that the friction force and abrasion area of skin substitute with the penetration of polyglycolic acid (PGA) multifilament surgical suture were larger than that of Nylon monofilament surgical suture. Meanwhile, more abrasion at the pull-in boundary of skin substitute was observed compared with that at the pull-out boundary.

Three novel xanthate-containing water-soluble triazine derivatives, 2,4-Di-(N,N-diethanolamine)-6-(ethyl xanthate ester-yl)-1,3,5-triazine (EXT), 2,4-Di-(N,N-diethanolamine)-6-(butyl xanthate ester-yl)-1,3,5-triazine (BXT) and 2,4-Di-(N, N-diethanolamine)-6-(hexyl xanthate ester-yl)-1,3,5-triazine (HXT), were synthesized and used as additives in water-glycol base fluid. It was found that the additive-containing samples had no corrosive effect on the cast iron and copper surface within 2.5 wt% additive. The tribological test results using a four-ball tribometer showed that the three additives greatly improved the P_B value, friction-reducing and antiwear performances of water-glycol. XPS results indicated that the additives had reacted with the contact metal surfaces and formed complex tribofilms composed of iron oxide, iron sulfide and iron sulfate, which may contribute to the reduction of friction coefficient and wear rate of the friction system.

Two triazine derivatives, 6-(diethanolamino)−2,4-bi-(sodium sulfanilate-yl)−1,3,5-triazine (STB) and 6-(ethyl xanthate)−2,4-bi-(sodium sulfanilate-yl)−1,3,5-triazine (STC) were synthesized and used as additives in water-glycol base fluid (mass ratio 1:1). Water solubility tests indicated that STB and STC met the solubility prerequisite for a water-soluble additive. The tribological tests by using a four-ball tribometer showed that, STB and STC both improved greatly the P_B value, antiwear and friction-reducing capacities of the base fluid. Based on friction test results and wear scars’ analysis, it was concluded that the differences in tribological performances of STB and STC samples were mainly due to the differences of the sulfur content and the sulfur activity in additives. XPS found that STB-tribofilm mainly contained sulfate, but STC-tribofilm additionally contained sulfide.

Tribological interactions between surgical suture and human tissue play an important role in the stitching process. The purpose of the paper is to understanding the tribological behavior of surgical suture interacting with artificial skin, with respect to surgical suture material and structure, by means of a capstan experiment approach and a contact area model. The results indicated that structure and surface topography of the surgical suture had a pronounced effect on the tribological interactions. The apparent coefficient of friction of vicryl surgical suture was the smallest among the three surgical suture materials. As the sliding velocity increased, or the applied load decreased, the coefficient of friction increased. Furthermore, stick-slip phenomena were observed during the sliding procedure.

Nowadays there is a wide variety of surgical sutures available in the market. Surgical sutures have different sizes, structures, materials and coatings, whereas they are being used for various surgeries. The frictional performances of surgical sutures have been found to play a vital role in their functionality. The high friction force of surgical sutures in the suturing process may cause inflammation and pain to the person, leading to a longer recovery time, and the second trauma of soft or fragile tissue. Thus, the investigation into the frictional performance of surgical suture is essential. Despite the unquestionable fact, little is actually known on the friction performances of surgical suture-tissue due to the lack of appropriate test equipment. This study presents a new penetration friction apparatus (PFA) that allowed for the evaluation of the friction performances of various surgical needles and sutures during the suturing process, under different contact conditions. It considered the deformation of tissue and can realize the puncture force measurements of surgical needles as well as the friction force of surgical sutures. The developed PFA could accurately evaluate and understand the frictional behaviour of surgical suture-tissue in the simulating clinical conditions. The forces measured by the PFA showed the same trend as that reported in literatures.

Graphene oxide (GO) was asymmetric chemically modified with myristyltrimethylammonium bromide (TTAB) to get modified graphene oxide (MGO). This MGO was used as an emulsifier and additive in oil-in-water emulsion. The emulsifying tests showed MGO greatly improved the stability of base emulsion and decreased its droplets size. Tribological test results showed that under the boundary lubrication condition with MGO-emulsion, the friction coefficient (COF) and the wear rate of the steel ball were decreased by about 18% and 48% respectively, comparing with base emulsion lubrication. The tribological mechanism of MGO-emulsion could be explained by the strong film-forming ability on the metal surface; the good lubricity of its small droplets; the formed adsorption film, transfer film and tribofilm between the contact surfaces.