The importance of skin processing technologies, in the history and dispersal of humankind around the planet cannot be overstated. This area of material culture is often underrepresented as a research topic, and has been hampered, in part, by the lack of a systematic analysis methodology targeted at specifically this material type. This research aimed to develop a methodology for determining the tanning technologies in use during prehistory, from extant archaeologically recovered processed skin objects. The methodology is a product of macroscopic and microscopic observations of a large sample reference collection, used to produce a database of defining characteristics and tendencies for each of six tannage types. The sample collection is made up of twenty-two species identified as economically important from both Europe and North America. Six sample pieces of skin were taken from a single individual of each of the twenty-two species, and processed using six tanning technologies, the use of which covered a large geographic area and time frame. A second reference collection of clothing and utilitarian items, made from traditionally processed skins, was used to add a section of in-life use traces to the database of discriminating traits. The developed methodology was tested by examining archaeologically recovered and ethnographically collected skin objects, from museum collections across North America and Europe. Objects from many different preservation contexts, including wet, dry, and frozen sites were analysed to determine whether or not the discriminating traits survived interment. It was found that defining characteristics and tendencies do exist between the main tannage technologies, and can be recorded at multiple levels of observation. The analysis of skin objects in museum collections confirmed that at least some defining characteristics and tendencies survived in all preservation contexts. In addition, the preservation of in-life use traces proved to be diagnostic of not only tannage type, but small sections of chaîne opératoire and object biography as well. Overall, this research has demonstrated that archaeologically preserved objects made from processed skin can provide information about the tannage technologies in use prehistorically, as well as more detailed information such as manufacturing sequences and the conditions of use an object was subjected to. Thus, analysis of this nature can be used to access information on a more individual level than previously believed.

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The tannin extract industry disposes of large volumes of condensate liquors evolved during concentration of weak leach liquors obtained by extraction of wood chips. The liquors are highly corrosive due to acetic acid contained therein along with lesser quantities of other organic substances common to woody materials. Recovery of the acetic acid would be desirable from two standpoints: (1) the value of the acetic acid, and (2) reuse of the acid-free condensate in the manufacturing process. The purpose of this investigation was to recover acetic acid from the wastes of tannin extract manufacture. An ion exchange process was given primary consideration to accomplish the recovery by adsorption of the acetic acid from the waste liquor with subsequent elution of the acid from the ion exchange material by use of stronger acid. Tests were conducted using De-Acidite, a synthetic aliphatic amine anion exchange resin produced by the Permutit Company, New York, N.Y.. For all tests 200 ml. of resin were used at temperatures within 20-30°C. A total acid-binding capacity of 19,700 grains CaCO₃/ft.³ was found when De-Acidite was exposed to 0.5 percent acetic acid in batch operation. Optimum rate of flow determinations in column operation within the range of 1 to 5 gal./ft.²/min. were conducted. Variations of flow rates between these limits failed to produce substantial differences in breakthrough capacities. To prepare the De-Acidite bed in the ion exchange column between runs regeneration was effected with 1 percent sodium hydroxide. Rinse was by downflow operation until data was obtained which indicated its unsuitability; thereafter backwash rinse was used and found more satisfactory. The waste liquor used in the investigation was obtained from the 2nd and 3rd effects of a triple effect evaporator employed in the Mead Corporation Plant at Lynchburg, Virginia. Successive exposures of De-Acidite to the waste liquor resulted in sharp reduction of breakthrough capacity, discoloration of the De-Acidite, and deterioration of the resin with the formation of fines. It was found that the extremely small quantities of tannin present in the waste liquor were the cause of the rapid depreciation of the De-Acidite. / M.S.

Skin cancer is a major public health concern, and tanning remains a modifiable risk factor. Multidimensional influences, including psychosocial, individual, environmental, and policy-related factors, create the milieu for individuals to engage in tanning. Parents and physicians can modify the behavior of teens and young adults using strategies based on harm reduction. Environmental and policy-related factors similar to those used to limit smoking by restricting access of minors to cigarettes in the United States in the 20th century need to be created. Federal regulations can restrict direct advertising and the excise tax can be increased to a prohibitive amount. Social networking may assist with affect regulation.

As skin cancer rates increase, it has become more important for at risk individuals to reduce ultraviolet radiation (UVR) exposure. Limited information is available on characteristics and behaviors of sunless tanning product users in populations with high sun-seeking behaviors. This information is important because use of sunless tanning products could reduce tanning through UVR exposure thereby leading to a reduction in skin cancer. Sorority and fraternity students (n=163) completed a self-administered questionnaire examining sun exposure and tanning attitudes, behaviors and beliefs. Characteristics of sunless tanning product users were compared to non-users using logistic regression accounting for potential clustering effects within sororities and fraternities. Among students surveyed, 34% reported ever using sunless tanning products. Ever users of sunless tanning products were significantly more likely to be female (OR=7.5), have fair skin (OR=1.4), have used tanning beds greater than 50 times (OR=2.5), and reapply sunscreen when outside on a sunny day (OR=1.3). Ever users of sunless tanning products and those with a preference for these products because they are safer than tanning beds or sunbathing were more likely to reapply sunscreen on a sunny day in the summer. However, other sun protection behaviors (i.e. sunscreen use, amount of sunscreen used, and avoidance of midday sun while on spring break) were not more likely to be adopted by these students. Prevention efforts could target these fair-skinned females to increase their use of sunless tanning products in combination with sunscreen use and reapplication along with avoidance of midday sun.

Content: In leather making processes, the thermal and non-thermal effect of microwave, especially non-thermal effect, strengthen the combination between collagen and chemicals. Although tanning under microwave makes the leather have better thermal stability, the tanning process and leather properties have not been studied in detail. For illustrating the influence of microwave on chrome tanning process, pickled skin was tanned for 6h as penetration procedure and then basified for another 4h as fixation procedure. The tanning under microwave heating (MW) was experimental sample and under water bath heating was control. UVVis, ICP-OES and pH meter were used to measure the changes of tanning effluent during tanning, and Shrinkage temperature meter, DSC, TG, FT-IR, SEM, XRD and XPS were applied to determine the differences between MW and WB in aspect of leather property and structure. The results indicated microwave accelerated chrome tanning agent penetration and had better promotion effect on chromium complex hydrolysis and olation. The leather tanned with microwave assisting had special effect on improve tanning effect which led better thermal stability and resistance of leather, but the collagen structure, including triple helix structure, stayed as WB and the combination mechanism between collagen and chromium was also same with conventional. In sum, microwave had positive effect on accelerating tanning rate and resulting in better leather without any negative effect on leather structure. Therefore, microwave would be a potential for achieving clean and sustainable chrome tanning by making tanning much faster and more efficiency. Take-Away: Microwave promotes chrome tanning agent penetration and combination Microwave has positive effect on tanning effect further as the leather tanned by microwave assisting has higher thermal stability. Although microwave promotes chrome tanning process, the collagen structure and tanning mechanism remained as normal.

Content: To reduce the environmental impact of tanneries at source for all types of leather, a series of investigations started at laboratory, then large pilot scale, to rationalise liming and tanning processes. This included the elimination of washes at the end of these processes, with retention of residual processing floats at maximum concentration as a chemical resource for reuse in subsequent processing. Adopted by four tanneries manufacturing more than 70,000 hides per week to the chromium tanned state, analysis detailing the equalisation of ions and solubles within these closed-loops was possible, and the subsequent release mechanisms. Large scale wet blue units specifically built to match the technology are now in the final stages of construction. From foundation level these differ from normal design, also uses of equipment, management of discharges, and plant operation. Low-impact chemical processing is locked into the fabric of these new tanneries. The technology has also spread to large scale nappa sheepskin production. And at cottage scale, thirty small tanneries in a tanning cluster processing sheep, goat, and bovine leathers to the wet blue are already changed their processing to meet a policy of no chromium discharges from their tanning areas by June 2019. The aims of low-impact manufacture, where the use of active chemicals is complete, quality fully maintained, and waste minimised are being met. This new approach to leather making offers considerable benefits at both large and small scale for wet blue manufacture. Take-Away: Closed loop systems for liming and tanning are highly effective in leather manufacture. Hight quality leathers can result fron this technology. There are considerable savings in chemical use and minimisation of waste water treatment.

Content: Leather and leather products are known for its durability and luxuries which makes it more unique among the other synthetic materials. Breathability and visco-elastic properties make leather unique choice of biomaterial. Utilization of leathers in marine based applications is limited owing to reactivity of leather towards salt and weather conditions. Moreover, the choice of raw materials and chemicals used during leather manufacture has greatly influence the properties of the leather. An attempt has been made to understand the influence of sea conditions on leathers. Conventional chrome tanned and vegetable tanned leathers were incubated in sea water and subsequently processed into post tanning to evaluate the physical properties. To understand, the leaching of chemicals, dyed leathers are incubated at different humidity and saline conditions. Interestingly, chrome tanned leathers found to be friendlier to marine conditions whereas, vegetable tanned leathers lead to leaching of chemicals. Furthermore, leaching of chromium is negligible, and crust leathers resulted in soft leathers. Prolonged exposure of chrome tanned leathers under salt stress leads to more softness. This might be due to saline stress to the skin matrix. Moreover, the computability of conventional leather chemicals were also tested using sea water. The research provides a new insight on fine tuning the chemicals to suit marine based applications. Take-Away: A new insight on fine tuning the chemicals to suit marine based applications.

Content: A copolymer has been synthesized from leather waste and monomer and its application has been studied for improved exhaustion in tanning and post-tanning processes. After synthesizing, the product has been analyzed and found to have particle size of 810 nm, pH of 4.0, relative viscosity of 0.8872 cp, polydispersity index (Mw/Mn) of 0.555 and percent solid as 23%. The weakly anionic character of the copolymer is supported by zeta potential of –0.0403 mV. The stability of the particle was also studied using TGA, DSC. Functional groups of the polymer was analyzed by FT-IR which revealed the presence of carboxylic acid, amide I & II, hydroxyl groups and ester groups in the product. The product can be used for increasing exhaustion and leather-properties in chrome tanning and post-tanning processes. It improves belly filling, provides fullness, softness and dye exhaustion in post-tanning process. It also shows better fullness and body in chrome tanning processes. The color properties found to be better and strength properties were comparable in experimental leather as compared to conventionally produced leather. This product can be applicable for manufacturing different types of leather where fullness and tightness are necessary. The present process helps in mitigating pollution problem of liquid and solid wastes of leather industry. A cost benefit analysis shows that the process is feasible for up-scaling. Take-Away: Synthesis of Co-Polymer from Leather Waste Application of Co-polymer as retanning agent Improved Exhaustion & Organoleptic Properties of leather

Content: Application of biocatalyst becomes an imperative due to their eco-friendly advantages. Enzymes in pretanning for unhairing, fiber opening, defleshing and bating are well reported and practiced. However, the role of enzymes as a chemical aids is less explored and consider as a secondary applications. Leather enzymes are known for its hydrolytic behavior which makes it more suitable for pretanning operations. However, typical chemical exhaustive aids acts as a vehicle for the diffusion of chemicals, whereas enzymes aids in the splitting of fibers which facilitate the diffusion of chemicals and create more functional sites for the tanning and post tanning chemicals to interact. In this research, pickled pelts are treated with acid protease and subsequently tanned using chrome tanning agent. Enzymatic treated pelts resulted in better uptake of chromium as compared to conventionally processed leathers. Similarly, after neutralization, chrome tanned leathers are treated with alkaline protease to conventional post tanning has been carried out. Enzymatic treated wet blue leathers showed high uptake of post tanning chemical, uniform dyeing and reduction in the pollution load. From the preliminary research, an interesting finding has augmented that application of enzymes at an optimized concentration, temperature, pH and time would lead to better uptake of chrome which reduces the pollution and minimization pollution load in post tanning. This study, emphasize on the application of enzymes in tanning and post tanning for higher diffusion of chemicals. Take-Away: 1. Replacement of conventional exhaustive aids using biocatalyst 2. Higher exhaustion rate of tanning and post tanning chemicals 3. Futuristic technology for sustainable leather manufacture