Wrapping Materials Research Articles

Characterization of PBAT/TPS blends for plastic wrapping materials of pathological waste buried in soil environments

This study investigates the incorporation of thermoplastic starch (TPS) into polybutylene adipate terephthalate (PBAT) to create biodegradable plastic wraps for pathological waste burial in soil. TPS is added to PBAT to enhance biodegradability, as PBAT alone degrades slowly. The research examines the mechanical properties, biodegradation, morphology, and swelling behaviour of the blends. Key tests include xenon arc light exposure for accelerated aging, a formalin swelling test for permeability, and soil degradation analysis for weight loss. Results show that adding TPS significantly reduces tensile strength (65.53%) and elongation at break (93.35%), but the material still effectively serves its purpose as a wrapping for pathological waste. Morphological analysis reveals phase separation, and UV exposure further decreases tensile strength by 27.6%. The highest TPS composition (30TPS/70PBAT) shows the fastest mechanical degradation, indicating accelerated biodegradation. Despite minimal formalin absorption (16% within 1 day), the blends prevent formalin leaching, making them suitable for pathological waste containment.

Model Test on Acoustic Emission Monitoring of Loess Slope Failure.

The three stages of loess collapse are characterized by notable concealment and sudden onset due to the sudden nature of loess collapse and the prolonged duration of the peristaltic deformation stage. Traditional displacement monitoring methods struggle to detect early signals of instability and failure, leading to poor timeliness in disaster warnings. This project begins by examining non-force field information related to the loess collapse process. It focuses on acoustic emission monitoring and employs model tests to identify effective waveguide rods for monitoring loess collapse. Additionally, the project investigates the evolution anomalies of acoustic emission parameters before and after loess collapse failure, aiming to establish early warning criteria for loess collapse based on acoustic emission. This work provides a theoretical basis for monitoring and early warning of loess collapses. This study evaluates five parameters of the active waveguide system: sensor installation method, filling material, waveguide rod wall thickness, outer wrapping material, and outer wrapping wall thickness. The densities of the filler materials were tested using the optimal parameters derived from the tests to identify the best configurations for active acoustic emission (AE) waveguide systems suitable for monitoring loess collapse. Subsequently, a one-sided connected loess collapse model was employed for indoor tests, integrating real-time AE monitoring with the active waveguide method. This model facilitates the exploration of AE response characteristics during loess collapse and the analysis of destructive forms of loess collapse and time-sequence evolution of AE ringing counts throughout the deformation and destruction process. Results indicate that using filler materials with high elasticity modulus, high compactness, and low Poisson's ratio, along with thin outer wrapping and waveguide rod walls, leads to strong AE signals. As deformation damage of loess collapse intensifies, the number of AE ringing counts notably increases. A rapid rise in cumulative ringing counts can indicate a "sudden increase", or the b-value may stabilize, providing precursor information for loess collapse.

Green synthesized CeO2 nanoparticles-based chitosan/PVA composite films: Enhanced antimicrobial activities and mechanical properties for edible berry tomato preservation.

The current study is intended to enhance unique bioactive and eco-friendly composite films following a simple solvent-casting approach by incorporating cerium oxide nanoparticles (CeO2 NPs) with a chitosan (CS)/polyvinyl alcohol (PVA) matrix. Antimicrobial activity, preservation impact, mechanisms for the edible berry tomatoes and physicochemical properties of the produced films were tested. FTIR, SEM-EDX, XRD, UV–vis spectroscopy and contact angle were used to characterize the films. Incorporated (3.0 wt%) CeO2 NPs practically developed composite film's thermal stability, structural, mechanical, bioactive, antioxidant, barrier and wettability properties. The tomatoes' look, weight loss and stiffness were better preserved after 25 days of storage at room temperature (25 ± 5 °C) when 3.0 wt% CeO2 NPs films were used instead of the original CS/PVA film. CS and CeO2 NPs have unique physiochemical and antibacterial properties. Food packaging extensively investigates the modified films as antimicrobials and preservatives to increase the shelf life of packaged foods, owing to their ability to inhibit gram-positive bacteria (Bacillus cereus and Staphylococcus aureus), gram-negative bacteria (Klebsiella pneumoniae and Pseudomonas aeruginosa), and filamentous fungi (Bipolaris sorokiniana, Fusarium op., and Alternaria sp.). Our findings indicated that the CeO2/CS/PVA composite films could be used as effective wrapping materials for food preservation.

Diversity, composition, and role of woody Non-Timber Forest Products in Tawangmangu, Central Java, Indonesia

Abstract. Haqqin F, Arkan F, Ibriza NM, Fadhilah RN, Safira RN, Dewangga A, Kusumaningrum L, Thenya T, Setyawan AD. 2024. Diversity, composition, and role of woody Non-Timber Forest Products in Tawangmangu, Central Java, Indonesia. Asian J Ethnobiol 7: 68-78. Forests have an important role in supporting biodiversity and providing various ecosystem services vital for human welfare; besides that, forests are also an important resource for Non-Timber Forest Products (NTFP), which are forest products other than timber used by local communities. NTFP can be categorized into fodder, firewood, food wrapping, medicinal plants, ornamental plants, spices, and food. The aim of this research was to analyze biodiversity and the use of NTFP in the villages of Plumbon, Nglebak, and Sepanjang, located in Tawangmangu Sub-district, Karanganyar District, Central Java, Indonesia. Data collection included interviews and field surveys. In the course of the interviews, a total of 62 respondents were engaged. The results showed that 83 plant species belonging to 41 families had been identified for many NTFPs such as (i) medicinal plant, (ii) food, (iii) ornamental plant, (iv) fodder, (v) spices; (vi) firewood; and (vii) food wrapping. The research findings indicate that Plumbon Village (Station A) exhibited the highest NTFP woody plant biodiversity value, with the highest values for each index component, i.e., 2.8 (H'), 5.9 (Dmg), and 0.765 (E). Each village is characterized by distinct dominant plant species: Melastoma malabatrichum dominates Plumbon Village (Station A), Manihot esculenta dominates Nglebak Village (Station B), and Calliandra houstoniana dominates Sepanjang Village (Station C). Notably, the plant with the highest use value is Tectona grandis, which serves as a medicinal plant, firewood, and food wrapping material. This research provides a deeper understanding of the biodiversity and use of NTFPs in the region, which has important implications for natural resource management and the well-being of local communities.

AIE-doped agar-based photodynamic sterilization film for antimicrobial food wrapping

Agar film for food wrapping is popular because of its low price, edible and strong biodegradability. However, there are still many problems in the application of agar film, such as no antibacterial performance. To address the problem, we designed and synthesized a novel photodynamic bactericidal aggregation-induced emission (AIE) molecule, then mixed it into agar to prepare a composite film, which made the agar film have antimicrobial properties. Due to the antimicrobial ability of the AIE molecules, the agar-based composite film doped with AIE has a good inhibitory effect on E. coli, S. aureus, C. albicans, A. baumannii, P. aeruginosa and P. leiognathi. The actual fresh-keeping performance of wrapped pork was evaluated, and the results showed that it could extend the shelf life of pork to more than 8 days. In addition, the light transmittance, mechanical properties, water resistance, water permeability and thermal stability of the composite film remain good. Therefore, the application of AIE-doped agar-based film in food antimicrobial wrapping materials has a good prospect.

Cycle Tests and Structure Repair of Bridge Pier Models

This research was conducted in anticipation of the risk of fatal damage to the structure due to the earthquake. In this study, experiments were carried out on the test object in the form of a bridge pillar model, which consisted of 2 test steps. The cyclic test is in the form of a pier bridge model and is continued in step 2 in the form of repairs with grouting and carbon wrapping materials as well as conducting another cyclic test to evaluate the performance of the repair materials used. This study uses the pier model, which consists of two test objects, namely a column with dimensions of 0.25x0.25x1.68 meters and a column cap of 1.20x0.55x0.36 meters. This test provides a constant axial load of 0.2 fc’.Ag and a cyclic lateral load. Phase 1 testing was carried out until the drift ratio was 3.5%. The achieved lateral peak strength is 8,606 tonf with a drift ratio of 2.20%. Lateral strength experienced a decrease in peak lateral strength of 86.93%. The damage is dominated by shear cracks which are characterized by the number of cracks with a diagonal pattern. Structural performance analysis was carried out according to ACI 374.1-05. The results of the theoretical analysis of the peak strength of the pier model were 15.2144 tonnes in the tensile direction, while the experimental ones were 8.606 in the pushing direction and -7.812 in the pulling direction.

Research on the heat resistance and electrical properties of fluorinated polyimide/nano-Al2O3/nano-Si3N4 composite materials

Polyimide (PI) refers to a polymer containing an imide ring characteristic structure on the main chain. It has excellent thermal stability, insulation properties and other characteristics. The Tesla transformer is the core component of the primary pulse source of the high-current electron beam accelerator. It is also an essential component of the energy storage pulse power supply. Therefore, it has broad application prospects in the fields of national defense and civil industry. If the insulation performance of the turn-to-turn coils of the Tesla transformer does not meet the standards, it will break down during high-voltage corona discharge, causing transformer failure. Therefore, it is crucial to improve the insulation performance of Tesla transformer inter-turn wrapping materials. The incorporation of fluorine-containing groups has proven to be a transformative strategy that significantly enhances the physical, chemical, optical, and electrical properties of PI films. In addition, numerous studies have demonstrated that introducing inorganic fillers into the polyimide matrix can substantially enhance the insulating properties of polyimide films. This paper specifically concentrates on elevating the insulating and thermal attributes of polyimide. Initially, a range of polyimide films was synthesized for performance assessment by employing various fluorinated dianhydride and diamine components, utilizing them as substrates. Then, we used nano-silicon nitride (nano-Si3N4) and nano-alumina (nano-Al2O3) as doping phases to prepare PI composite films, which reduced the dielectric constant and increased the breakdown strength.

Repair of Pier Bridge Model Post-Earthquake

This study concentrates on the bridge pier model which was damaged by the earthquake and repaired using grouting and carbon wrapping materials. This research consists of a one pier bridge model with two steps of testing, namely step 1 in the form of a cyclic test of the pier bridge model which will be followed by step 2 in the form of structural repairs with grouting and carbon wrapping materials and retesting. to evaluate the performance of the structural repair technology used. This research will show the cyclic test results using the repair material applied to the same sbr latex concrete material test object. The test object used is a pier bridge model with dimensions of 0.25×0.25×1.68 meters. The material specifications used are concrete f'c 30, fy 400 MPa deformed longitudinal reinforcement and stirrups fy 240 MPa. The test was carried out with a constant axial load of 0.2.f'c.Ag and a cyclic lateral load. Structural performance analysis was carried out according to ACI 374.1-05. Step 1 cyclic test was carried out until the drift ratio was 3.5%. The lateral peak strength achieved was 8.606 tonf with indications of shear damage indicated by the number of cracks in the web area. The second step of the cyclic test was carried out to a drift ratio of 6.25% with a lateral peak strength of 8.640 tonf with indications of flexural damage. Cyclic test results show that repair with a grouting material and carbon wrap can restore peak strength, deformation capacity, and stiffness degradation.

Follow effect of low cost glass fibre reinforced polymer (GFRP) on the performance of concentrically loaded concrete column

(FRP) plays a major role in the strengthening of existing structures due to the age of the structure or natural calamities like earthquakes, floods, cyclones, etc. For reducing the size of structural members, the FRP wrapping assists to achieve the performance of the structure. Concrete is widely used due to its advantages and FRP is added to improve its quality in terms of strength. A study has been conducted on 21 cylinders based on their slenderness ratio. The slenderness ratios in the columns were 8, 16, and 24. At thicknesses of 5 mm and 7 mm, two types of wrap materials (UDCGFRP) and (WRGFRP)] were employed. Up to the point of failure, the columns were subjected to monotonic axial compressive force. The column’s yield loads, and ultimate load, were deduced from the load-deflection curves. The overall, uni-directional cloth provided the most effective confinement and led to a highly desirable failure mechanism, which was a gradual process.

Effect of Wrapping Materials Combination of Growth Regulators on Physical Characters and Storage Life of Papaya (Carica papaya L.) cv Red Lady

The experiment was conducted to assess the effect of different wrapping materials and growth regulators on physical characters, storage life and quality of papaya cv Red lady was stored at room temperature during the investigated. The fruits are harvested best treatment of INM (i.e 75% RDF+10 kg vermicompost + 100 g Azotobacter + 100 g PSB plant-1) fruits harvested dipped in different growth regulators and combined with packaging materials imposed in the present investigation showed lowest loss in weight (PLW) in fruits treated with CaCl2 @ 3.0% and packed with news paper (7.65%), whereas, highest PLW was found in control (38.93%). Maximum fruit firmness was observed in the fruits treated with T1- CaCl2 @ 3.0% and wrapping with news paper (2.03 kg cm-2) and T1 recorded significantly minimum spoilage (23.34%) over other treatments. Maximum TSS recorded in T7 control (10.80 OBrix). The storage life was found maximum in T1 - fruits dipped in CaCl2 @ 3.0% and wrapping with news paper (17.58 days) and followed by T3- GA3 @ 100 ppm and wrapping with news paper (16.25 days). However, control has shown poor storage life (9.00 days).

How does product packaging features influence the purchase decision of young adult?

Packaging is more than just a suitable way of showcasing a product or getting a product to the consumer without reaching any damage. Here, we intended to know the relative significance of different features of packaging in purchase decision-making. We controlled the diversity of products and their confounding effect in the decision-making task by giving participants a particular product category (toiletries items) in the instruction. A survey was conducted on 386 Bangladeshi adult participants to rate their attitudes toward 11 different packing features when they make a purchase decision. The finding shows that participants rated printed detail on the package as the most important attribute which can manipulate their purchase choice. Moreover, they rated Convenience packaging, Hygienic wrapping material, convincing words on the packet, and attractiveness as the top five packaging features for young Bangladeshi adults, respectively. We found some significant gender differences in four features of product packaging. Bangladeshi adult females are more influenced by the attractiveness, colourful packet, convenience packaging, and convincing words on the packet than male customers. This finding could be an important addition to consumer behaviour literature. Moreover, marketers and designers would know their customer's needs and will be able to use this knowledge in product packaging as a reliable source of marketing strategy to increase their product sales.Keywords: product packaging; consumer behaviour; decision making; young adults

Effect of Different Packaging Materials and Various Levels of Nanosilver on Cut Rose

An experiment was conducted in CRD, in which two factors were evaluated viz., different wrapping materials and different levels of Silver Nano Particles were taken to observe the effect of shelf life of cut rose. Different levels of SNP were at 10,20,30, and 40 ppm along with wrapping materials such as- Butter paper, LDPE, aluminium foil and newspaper as control used in refrigerated condition. Present study concluded that cut roses had longest shelf life at 30 ppm NS (Nano Silver) and BC ratio was highest in T 16 (AF + 0 ppm NSP).

Tow placement effects on fiber waviness and tensile performance of 3D-tow reinforced hybrid-molded composites

Three-dimensional (3D) tow reinforced hybrid molding combines continuous fiber composite tow with injection overmolding to improve mechanical performance of molded components, but tensile performance is not accurately captured by conventional modeling processes. When wrapped around load introduction points, the fibers of a thick tow traverse a shorter distance at the inner radius than the outer radius leading to waviness on the inner region of each wrap. The Hsaio and Daniel model was used to predict local elastic properties of the wavy fiber composite and spatially varying material properties were applied to 3D finite element models of a suspension link. Neglecting fiber waviness overpredicted experimental tensile stiffness and strength by 36% and 33% respectively while modeling waviness overpredicted stiffness and strength by only 9% and 14% respectively. Tow wrap configuration, waviness propagation, and material parameters have significant effect on tensile performance while the tow has little effect on compressive performance.

SG-APSIC1130: Zero wet pack Pimporn Sirikraiwattanawong, Thailand

Objectives: We noted moisture in Thompson retractor sets after steam sterilization in our hospital. Moisture can cause severe problems leading to potentially contaminated instruments that carry infection risk to patients and cause procedure delays, wasted time and effort, greater workload, and higher costs. We sought to reduce the number of retractor sets with moisture to zero. Methods: The central sterile supply (CSS) team discussed the cause of the problem. We hypothesized that temperature difference between the sterilizer chamber and inside the container might create condensation and thus moisture in the final surgical set. We collected and analyzed data and proposed an experiment to improve the sterilization process. We performed a trial of sterilization process improvements pertaining to proper loading technique and the packaging process. We also evaluated the appropriate drying time for rigid containers. We then rearranged the process and adjusted the cooling time from 30 to 60 minutes after steaming. Results: Moisture in Thompson retractor packs occurred because of thicker, rigid containers. We removed the previous type of lining material to separately steam the rigid surgical instrument, and we extended the cooling time to 60 minutes. We updated standard operation procedures and continued to monitor and re-evaluate the process. Conclusions: We identified the primary cause of moisture in Thompson retractor sets after steam sterilization. We illustrated that avoiding sterilizer overload, avoiding contact with fabric wrapping materials, and proper cooling time kept the pack moisture free. Occurrences of moisture in surgical packs after sterilization should be reported and handled efficiently by CSS personnel to preserve quality and avoid waste.

Antioxidant activity and identification of flavonoid compounds in Patat leaves (Phrynium capitatum) ethyl acetate extract

Flavonoids are the biggest compound from the phenolic group that has the function of antioxidants. One of the plants with flavonoids is patat (Phrynium capitatum), which is usually used as food wrapping material. This study aims to quantify total flavonoid content, antioxidant activity and identify flavonoids from patat leaves ethyl acetate extract. Patat leaves sample cleaned, dried, and grinded. Grinded patat leaves were macerated gradually for 2 × 24 hours with n-hexane, ethyl acetate, and methanol solvent. The extract undergoing total flavonoids test guided with AlCl3 and CH3COONa. Extract with the biggest flavonoids content proceed to antioxidant activity test by SOD (superoxide dismutase) method and analyzed for the flavonoid structure by UHPLC MS/MS (ORBITRAP HRMS). The biggest total flavonoids are ethyl acetate extract with 8.678 mg QE/g; then methanol extract with 5.296 mg QE/g; and n-hexane extract was not tested because of negative results in the qualitative test. The antioxidant activity of the ethyl acetate extract of patat leaves is classified as inactive, with an Ic50 value of 488.299 ppm. The low antioxidant activity is due to the sample, which is still a matrix containing many compounds. The flavonoid compounds identified by its fragmentation pattern were kaempferide, formononetin, and pinostrobin.

Valorisation of fruit peel bioactive into green synthesized silver nanoparticles to modify cellulose wrapper for shelf-life extension of packaged bread

Fruit peels are rich source of bioactive compounds such as polyphenols, flavonoids, and antioxidants but are often discarded as waste due to limited pharmaceutical and nutraceutical applications. This study aimed to valorise pomegranate and citrus fruit peel into green synthesised silver nanoparticles (AgNPs) in order to modify cellulose-based wrapping material for prospective food packaging applications and propose an alternate and sustainable approach to replace polyethene based food packaging material. Four different concentrations of AgNO3 (0.5 mM, 1 mM, 2 mM, and 3 mM) were used for green synthesis of AgNPs from fruit peel bioactive, which were characterised followed by phytochemical analysis. Ultraviolet–Visible spectroscopy showed surface plasmon resonance at 420 nm, XRD analysis showed 2θ peak at 27.8°, 32.16°, 38.5°, 44.31°, 46.09°, 54.76°, 57.47°, 64.61° and 77.50° corresponding to (210), (122), (111), (200), (231), (142), (241), (220) and (311) plane of face centred cubic crystal structure of AgNPs. Fourier-transform infrared spectroscopy analysis of AgNPs green synthesised from pomegranate and kinnow peel extract showed a major peak at 3277, 1640 and 1250–1020 1/cm while a small peak at 2786 1/cm was observed in case of pomegranate peel extract which was negligible in AgNPs synthesized from kinnow peel extract. Particle sizes of AgNPs showed no statistically significant variance with p > 0.10 and thus, 2 mM was chosen for further experimentation and modification of cellulose based packaging material as it showed smallest average particle size. Zeta potential was observed to be nearly neutral with a partial negative strength due to presence of various phenolic compounds such as presence of gallic acid which was confirmed by ultrahigh performance liquid chromatography-photodiode array(UHPLC-PDA) detector. Thermal stability analysis of green synthesised AgNPs qualified the sterilisation conditions up to 100 °C. AgNPs green synthesized from both the peel extracts had higher polyphenolic content, antioxidant and radical scavenging activity as compared to peel extracts without treatment (p < 0.05). The cellulose based food grade packaging material was enrobed by green synthesised AgNPs. The characterisation of modified cellulose wrappers showed no significant difference in thickness of modified cellulose wrappers as compared with untreated cellulose wrapper (p > 0.42) while weight and grammage increased significantly in modified cellulose wrapper (p < 0.05). The colour values on CIE scale (L*, a* and b*) showed statistically significant increase in yellow and green colour (p < 0.05) for modified cellulose wrappers as compared to control wrapper. The oxygen permeability coefficient, water vapour permeability coefficient, water absorption capacity and water behaviour characteristics (water content, swelling degree and solubility) showed significant decrease (p < 0.05) for modified cellulose wrapper as compared to control wrapper. A uniform distribution and density of green synthesised AgNPs across cellulose wrapper matrix was observed through scanning electron microscopy (SEM) images with no significant aggregation, confirming successful enrobing and stable immobilisation of nanoparticles from cellulose matrix. A seven-day storage study of bread wrapped in modified and control cellulose wrappers showed delayed occurrence of microbial, yeast and mould count in bread packaged in modified cellulose wrappers and thus, resulting in shelf life extension of bread. The results are encouraging for the potential applications of modified cellulose wrappers to replace polyethene based food packaging.

Effect of Geometric Arrangement on Mechanical Properties of 2D Woven Auxetic Fabrics

Textiles-fibres, yarns and fabrics are omnipresent in our daily lives, with unique mechanical properties that fit the design specifications for the tasks for which they are designed. The development of yarns and fabrics with negative Poisson’s ratio (NPR) is an area of current research interest due to their potential for use in high performance textiles (e.g., military, sports, etc.). The unique braiding technology of interlacement for preparation of braided helically wrapped yarns with NPR effect with later development of auxetic woven fabric made it possible to avoid the slippage of the wrapped component from the core. The applied geometrical configuration and NPR behaviour of the braided helical yarn structure with seven different angles comprising of monofilament elastomeric polyurethane (PU) core with two wrap materials that include multifilament ultra-high molecular weight polyethylene (UHMWPE) and polyethylene terephthalate (PET) fibres were investigated and analysed. The mechanically stable 2D woven textile auxetic fabrics (AF) with various weave patterns such as 2/2 matt and 3/1 twill were developed from the auxetic yarn with PU elastomer core having maximum NPR effect of −1.70 using lower wrapped angle of 9° to study and compare their mechanical responses. The auxetic yarn was used in weft direction and multifilament UHMWPE yarn in warp direction, using semi-automatic loom. Auxeticity of AF was analysed and its various mechanical properties such tensile strength, impact energy absorption, in-plane, and out-of-plane auxeticity, and puncture resistance were studied. Higher energy absorption of 84 Nm for matt fabric was seen compared to twill fabric having an energy of 65 Nm. The puncture resistance capability of matt fabric was better than twill fabric. While twill fabric exhibited better auxetic effect in both in-plane and out-of-plane mode compared to matt fabric. In short, both the twill and matt design AF’s showed unique characteristics which are beneficial in making various protective textiles such as protective helmets, bullet proof shields, cut resistance gloves, blast resistant curtains, and puncture tolerant elastomeric composites.

Qualification de stérilisateurs à basse température au peroxyde d’hydrogène : vers une meilleure harmonisation des pratiques ?

Comparing performance qualification procedures for low temperature vaporized hydrogen peroxide sterilization. Assessing conformity with draft standard ISO/DIS 22441. Qualification reports from several providers have been compared according to specific criteria: choices of cycles, loads, sterile barrier systems, probes, biological and chemical indicators; checking of packaging integrity and exposure to sterilizing agent. Six out of 8reports based on 4distinct sterilizers have been performed by third-party providers. Routine and process challenge devices are respectively used in 6and 3of these reports. Sizes and masses are never mentioned whereas load configuration is always specified. All reports use at least one biological indicator and 50% of them use one chemical indicator at a minimum. Most frequent wrapping materials are Ultra® and Tyvek® bags (respectively 50% and 37.5% of reports). Each qualification monitors per process pression and temperature, and 37.5% of them also quantify hydrogen peroxide concentration. Packaging integrity and environmental exposure are checked in respectively 50% and 12.5% of all reports. All reports have received providers approval. Qualification procedure is based on steam sterilization NF EN 14937standard, which seems unsuitable for low temperature process. The lack of autonomy, the heterogeneity of loads and measurement choices reveal a low harmonization of practices. New standard should dispel the doubts about this heterogeneity.

A comparison between TGA, SEM-EDX and Raman spectroscopy to assess PVC plasticizer loss

The migration of DINP and ESO plasticizers from PVC in contact with different wrapping materials was studied during artificial aging by combining three analysis methods. Silk paper, LDPE and PET were selected since these materials are widely used to protect PVC in heritage collections. First, Scanning Electron Microscopy (SEM) images and Energy Dispersive X-ray (EDX) analyses confirmed the presence of a plasticizer film at the surface of aged PVC whatever the wrapping material. Plasticizer loss during aging was then investigated after PVC surface cleaning. The overall loss of plasticizers was determined from Thermogravimetric Analysis (TGA) however it appeared to be skewed by the dehydrochlorination state. EDX analysis allowed to follow the plasticizer loss through the oxygen to carbon ratio although an external contamination was detected for some samples. Raman spectroscopy was the only technique providing the quantification of both ESO and DINP plasticizers across aging time. The combination of the three techniques to study the aging of PVC under different conditions thus highlighted the strengths and limits of each one. Finally, the relative mass loss speed was similar for both plasticizers but strongly dependent on the wrapping material. Whereas silk paper and LDPE slowed down the plasticizer loss, acceleration was evidenced in presence of PET.

Development of Auxetic Braided Yarns and Study the Effects of Braid Angle and Material Modulus on the Negative Poisson’s Ratio

This paper introduces the braided helically wrapped yarns with negative Poisson’s ratio (NPR) exhibiting a stable structure and good practicability to avoid slippage of wrapped component from the core. The geometry and auxetic behavior of the braided helical structure for two different combinations of core materials with similar combination of wrap materials and different braiding angles have been analyzed. Two elastomeric materials i.e. Polyurethane (PU) and Polyester, were used as monofilament cores whereas two stiffer multifilament wrap yarns employed were, ultra-high molecular weight polyethylene (UHMWPE) and polyethylene terephthalate (PET). Multiple braided yarns were investigated to analyze materials’ behavior towards NPR. It was observed that the NPR strongly depended on the inherent properties of the core and wrap materials in addition to the braiding angle. The NPR value was higher for a core with relatively higher elasticity (e.g., PU elastomer compared with polyester). It was also noticed that a lower wrap angle and lower braiding speed exhibited higher NPR. The maximum NPR value using PU core wrapped at a low angle of 9° was-1.70, when tested at a low strain rate of 0.5%.