COMPARATIVE STUDY OF RUBBER HOUSEHOLD GLOVES STANDARD

<p>Rubber gloves are widely used for hand protection in medical, food industries, and household purposes. The Indonesian national standard (SNI) that regulates quality specifications of these products is SNI 06-1301-1989, while for international standard is ISO 20057:2017. This study aimed to assess whether or not the SNI 06-1301-1989 needs to be updated referred to ISO 20057:2017 using comparative analysis. Eight samples of rubber household gloves have tested using ISO 20057:2017 as guidance. The result treated using descriptive analysis method then SNI 06-1301-1989 and ISO 20057:2017 were being compared. The result showed that only 4 samples namely G1, G2, G3, and G8 fulfilled requirements. Based on the result, several update were recommended for SNI 06-1301-1989 following ISO 20057:2017. Specifications such as letter and number size code and whether the gloves are ambidextrous or hand specific should be on the package. A uniform finish, free from discoloration appearance also width, length and thickness dimension and pH test needs to follows ISO 20057:2017 since latex allergen is can be found. Physic test i.e. tensile strength and elongation at break at standard laboratory temperatures and humidity and tensile strength after ageing should be kept as well as liquid for immersion test while tear strength and permanent set at 200% was unnecessary.</p>

Hydrolytic Aging in Rubber-Like Materials: A Micro-Mechanical Approach to Modeling

The effect of hydrolytic aging on mechanical responses of Rubber likes materials, in particular, Mullins effect and the permanent set has been modeled. Hydrolytic aging is considered as the result of the competition between two phenomena (1) chain scission and (2) cross-link scission/reformation. Both phenomena were modeled and thus, the strain energy of the polymer matrix is written with respect to three independent mechanisms; i) the shrinking original matrix which has not been attacked by water, ii) conversion of the first network to a new network due to the reduction of the crosslinks, and iii) energy loss from network degradation due to water attacks to ester groups. The model is validated with respect to a set of experimental data. Besides accuracy, the simplicity and few numbers of fitting parameters make the model a good choice for further implementations.

Investigation of the Effect of Carbonyl Iron Micro-Particles on the Mechanical and Rheological Properties of Isotropic and Anisotropic MREs: Constitutive Magneto-Mechanical Material Model

This article focuses on evaluating the influence that the addition of carbonyl iron micro-particles (CIPs) and its alignment have on the mechanical and rheological properties for magnetorheological elastomers (MREs) fabricated using polydimethylsiloxane (PDMS) elastomer, and 24 wt % of silicone oil (SO). A solenoid device was designed and built to fabricate the corresponding composite magnetorheological material and to perform uniaxial cyclic tests under uniform magnetic flux density. Furthermore, a constitutive material model that considers both elastic and magnetic effects was introduced to predict stress-softening and permanent set effects experienced by the MRE samples during cyclic loading tests. Moreover, experimental characterizations via Fourier transform infrared (FTIR), X-ray diffraction (XRD), tensile mechanical testing, and rheological tests were performed on the produced MRE samples in order to assess mechanical and rheological material properties such as mechanical strength, material stiffness, Mullins and permanent set effects, damping ratio, stiffness magnetorheological effect (SMR), and relative magnetorheological storage and loss moduli effects. Experimental results and theoretical predictions confirmed that for a CIPs concentration of 70 wt %, the material samples exhibit the highest shear modulus, stress-softening effects, and engineering stress values when the samples are subject to a maximum stretch value of 1.64 and a uniform magnetic flux density of 52.2 mT.

Pseudo-Elastic Analysis with Permanent Set in Carbon-Filled Rubber

Via cyclic loading and unloading tests of natural/styrene-butadiene rubber (NSBR) blends at room temperature, the effects of the stretching, rate, temperature, and volume fraction of carbon black in the filled rubber on a permanent set (residual strain) were studied. The results showed that increasing the stretching, rate, and volume fraction of carbon black and reducing the temperature yielded greater residual strain. The uniaxial tensile behaviors of composites with the Mullins effect and residual strain were simulated using the ABAQUS software according to the aforementioned data. An Ogden-type constitutive model was derived, and the theory of pseudo-elasticity proposed by Ogden and Roxburgh was used in the model. It was found that the theory of pseudo-elasticity and the Ogden constitutive model are applicable to this composite, and if combined with plastic deformation, the models are more accurate for calculating the residual strain after unloading.

MODULAR PLATFORM TO MODEL PARALLEL INELASTIC MECHANISMS IN RUBBER-LIKE MATERIALS

ABSTRACT Cross-linked rubber-like materials exhibit an elastic behavior with several inelastic features such as the Mullins effect, Payne effect, permanent set, deformation-induced anisotropy, and hysteresis. Although these features are being modeled individually, few attempts have been made toward systematic integration of these models into one model to consider damage accumulation in rubber-like materials. A new platform is presented to couple constitutive models of different inelastic mechanisms into one generalized model that can simultaneously consider them all. The kinematic structure of the proposed approach is based on two concepts: (1) the concept of microsphere and (2) the concept of network decomposition. The polymer matrix is decomposed into a number of parallel networks, in which each network describes one inelastic feature and is represented by one microsphere. Accordingly, the energy of the polymer matrix, $\Psi$, is the summation of the energies of the parallel networks. A network is considered as a three-dimensional (3D) assembly of unidirectional subnetwork elements distributed in all spatial directions represented by one microsphere. Such structural breakdown allows us to simplify different inelastic mechanisms as 3D assemblies of one-dimensional (1D) elements that host simplified 1D inelastic mechanisms. This concept replaces the complex 3D formulations of finite inelasticity based on the multiplicative decomposition of the F by a simple solution that can be further scaled up and integrates other models. The microsphere enables us to derive the stretch and the deformation history for each direction. Modular design of the platform allows models to be replaced anytime. Any ill-performing or expensive model can be later substituted by an improved version or temporarily deactivated. To validate the concept, a platform is proposed that can host models of permanent set, hysteresis, and Mullins effect. The accuracy of the platform is evaluated in comparison with experimental data and with respect to different models.

Influence of Zinc Oxide Nanograins on Properties of Epoxidized Natural Rubber Vulcanizates

Zinc oxide (ZnO) nanograins are synthesized by precipitation method filled epoxidized natural rubber compared to conventional ZnO. The synthesized ZnO nanograins are characterized by X-ray diffraction and transmission electron microscopy and found that average primary size of ZnO synthesized around 40 nm and the specific surface area of 28.72 m2 g-1. Furthermore, the cure characteristics, rubber mechanical properties and permanent set were investigated. The obtained results are found that the ZnO nanograins significantly affected to cure characteristics, rubber mechanical properties and permanent set. This is due to small grain size and large specific surface area.