Leather and Footwear Journal

Volume 15, no 2

Contents
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Care of Patient Lying with Varied Supine Angles: A Quantitative Pressure Evaluation
- Pages 61-72
  Jin ZHOU^1,2, Jianxin WU², Yaoxia LIU³, Bo XU¹, Wuyong CHEN^1,4*
  - ¹National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, P. R. China, email: wuyong.chen@163.com
  - ²Science Lab, Zhejiang Red Dragonfly Footwear co., LTD, Wenzhou 325105, P. R. China
  - ³Sichuan Provincial People's Hospital, Chengdu 610000, P. R. China
  - ⁴Key Laboratory for Leather Chemistry and Engineering of the Education Ministry, Sichuan University, Chengdu 610065, P. R. China
  ABSTRACT. The aim of this study was to clarify the pressure distribution of patient lying with varied supine angle on the standard hospital mattress (SHM) and sheep skin mattress (SSM), and then to compare the pressure relieving of those two kinds of mattresses which have been widely used in the pressure prevention. Eighteen healthy students were recruited from the university. Pressure distribution of SHM and SSM were measured by mFLEX measurement system in the supine angle of 0°, 30°, 60° and 90°. Pressure areas were divided into four parts: total, back, sacrum and heel area, under which peak pressure (PP) (mmHg), mean pressure (MP) (mmHg) and contact area (CA) (cm2) were calculated. One-way ANOVA shows that with the supine angle change from the level to the vertical status, PP and CA at sacrum area was increasing as well, but PP at sacrum was still high in the 90° supine angle; further Paired T test records that majority PP values were proved to be significantly reduced by the usage of SSM in each supine angle, in contrast with the control group of standard hospital mattress and pressure reduction of MP was limited. Although positive outcomes were observed in each supine angle when the SSM was applied, further improvement of SSM in the aspect of shape was still required, such as a 3D structure was introduced to lower the higher pressure at the sacrum area.
  
  KEY WORDS: bed sores, pressure ulcer, mattresses, nursing assessment, nursing care
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Comparative Study Regarding Leather Biodegradability
- Pages 73-84
  Rodica Roxana CONSTANTINESCU, Viorica DESELNICU*, Marian CRUDU, Gabriela MACOVESCU, Luminița ALBU
  - INCDTP - Division Leather and Footwear Research Institute, 93 Ion Minulescu st., Bucharest, Romania, email: vdeselnicu@gmail.com
  ABSTRACT. This paper presents a comparative study regarding the biodegradability of three types of organic tanned leathers: vegetable tanned leather, leather tanned with oxazolidine and leather tanned with resorcinol - oxazolidine, and three types of leather tanned with inorganic tanning agents: based on Chromium (III), based on Ti-Al, based on Ti-Zr. For assessment of leather biodegradation, EN ISO 20200:2005 was used as method. Physical-chemical analyses were performed on leathers at day zero and after 90, 120 and 220 days of composting. The conclusion of the study is that all types of tanned leather studied undergo the biodegradation process, but at different rates. The leather tanned with oxazolidine and vegetable tanned leather are more biodegradable than leathers tanned with resorcinol-oxazolidine. The leather tanned with resorcinol-oxazolidine is more stable at biodegradation.
  
  KEY WORDS: organic tanned leather, vegetable tanned leather, biodegradation
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A Liming Process with Sodium Silicate Compound as a Swelling Agent
- Pages 85-94
  Xiaoyun JIAN¹, Bo TENG¹, Jinwei ZHANG¹, Yanping GAO¹, Wuyong CHEN^{1, 2*}
  - ¹National Engineering Laboratory for Clean Technology of Leather Manufacture, 610065, Chengdu, China, wuyong.chen@163.com
  - ²Key Laboratory for Leather Chemistry and Engineering of the Education Ministry, 610065, Chengdu, China
  ABSTRACT. Low modulus sodium silicate was prepared with a polysilicon byproduct-silicon tetrachloride, and used as a swelling agent. Calcium chloride, hydrazine and protease were selected as auxiliaries for the swelling agent. Dosage of the auxiliaries was optimized through the weight increase, thickness increase, proteoglycan removing and skin histology in swelling. Based on the auxiliary optimization, a sodium silicate compound with 67% sodium silicate, 17% hydrazine and 3% protease (SSC swelling agent) was prepared as a swelling agent and its swelling ability was investigated with SEM and proteoglycan removing analysis. Also, the environmental impact of the swelling process was evaluated by total solid of the effluent. The results showed that a comparable opening up of fiber bundles was obtained with 6% SSC swelling agent (based on the unhaired weight) and proteoglycan removal in the skin was improved. Compared with a traditional liming process, there was a less total solid in the effluents. The results could provide a new valuable reference for cleaner swelling process.
  
  KEY WORDS: leather making, liming, swelling, sodium silicate, polysilicon
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Dynamically Cured Polymer Composite Based on PP and EPDM for the Footwear Industry
- Pages 95-106
  Mihaela NIȚUICĂ^{1, 2*}, Aurelia MEGHEA², Laurenția ALEXANDRESCU¹, Roxana TRUŞCĂ³, Ovidiu OPREA²
  - ¹INCDTP - Division Leather and Footwear Research Institute, 93 Ion Minulescu St., sector 3, Bucharest, icpi@icpi.ro, mihaela.nituica@icpi.ro
  - ²University POLITEHNICA of Bucharest, Faculty of Applied Chemistry and Materials Science, 1 Ghe. Polizu St., sector 1, 011061, Bucharest, Romania
  - ³METAV-CD, 31 C.A. Rosetti St., sector 2, Bucharest, Romania
  ABSTRACT. The aim of this paper is to obtain a dynamically cured polymeric composite based on polypropylene and ethylene-propylene-diene-terpolymer rubber, compatibilized with polypropylene-graft-maleic anhydride and added crosslinking agents (dicumyl peroxide). Performance of polymeric structures depend on the concentration and morphology of the elastomer and plastomer used, processing parameters, type and concentration of auxiliary materials used in compounding and of course, on the equipment and working parameters. The polymeric composite was made using the extrusion-granulation technology, so that it could be processed by molding and electrical pressing, at the optimum processing parameters. The resulting polymeric composite was tested in terms of its physical-mechanical properties (normal state and accelerated ageing at the temperature of 70°C, for 168 h) and structural properties, employing appropriate techniques.
  
  KEY WORDS: polymeric composite, EPDM rubber, polypropylene, compatibilizer
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Effect of Artificial Acid Rain on Aluminium Tanned Leather
- Pages 107-116
  Yanping GAO^1,2, Shuang YANG^1,2, Xiaoyun JIAN^1,2, Lucreția MIU³, Carmen GAIDĂU³, Wuyong CHEN^1,2*
  - ¹Key Laboratory of Leather Chemistry and Engineering of the Ministry of Education, Sichuan University, Chengdu, 610065, P. R. China, email: wuyong.chen@163.com
  - ²National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, P. R. China
  - ³INCDTP - Division: Leather and Footwear Research Institute, 93 Ion Minulescu St., sector 3, 031215, Bucharest, Romania
  ABSTRACT. This article aims at studying the influence of gaseous pollutants on aluminium tanned leather. Artificial acid rain was used to soak the aluminium tanned collagen materials for 0, 4, 8, 12 and 16 days, then some analytical techniques were used to evaluate the changes of leather during the aging process. Micro hot table (MHT), differential scanning calorimetry (DSC) and thermogravimetry (TG) were used to evaluate the influence of artificial acid rain on thermal behaviors. Scanning electron microscope(SEM) was used to investigate the changes of fibrous morphology during aging process. Fourier transform infrared spectroscopy (FT-IR) was used to investigate the changes of structural property after artificial acid rain treatment. With the extension of aging time, thermal stability and heat resistance were gradually reduced, including shrinkage temperature, thermal denaturing temperature, associated enthalpy, weight loss and temperature for maximum decomposition rate. SEM images showed that the collagen fibers were greatly damaged, the gaps among fibres were disappeared and the fibre bundles were randomly ruptured with the aging time. The FT-IR results showed that, during the aging process, amide A band was moved to higher numbers, amide I and amide II band of collagen were gradually shifted to lower numbers. Consequently, the structure and performance of aluminium tanned leather were damaged by artificial acid rain and the longer the aging time is, the greater the damage is.
  
  KEY WORDS: leather making, aluminium tanned leather, artificial acid rain, aging
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