Preparation and characteristics of nano-B4C/PVA particles and ultra high molecular weight polyethylene composites

Abstract

In-situ mechanical process for preparation of the polyvinyl alcohol (PVA) coated nano-B 4 C powder was investigated by using a high-energy ball mill. The produced PVA coat on the surface of nano-B 4 C particles was observed by x-ray diffraction (XRD) and confirmed by TEM images. The average particle size of the produced nano-B 4 C/PVA particles was in the range of several tens to hundreds of nanometers depending on the milling conditions. The polymer composites were fabricated by hot pressing ultra high molecular weight polyethylene (UHMWPE) powder mixed with nano-B 4 C/PAV and micro-B 4 C powders, respectively. Nano-B 4 C/PVA dispersed UHMWPE shows slightly lower crystallinity and stiffness than micro-B 4 C dispersed UHMWPE based on differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) evaluations.

Air and Water Vapor Permeable UHMWPE Composite Membranes for X-Ray Shielding

“…arrow), for most of the semicrystalline structure of LDPE had changed to an amorphous structure during the milling process. 13,14 Figure 3 shows the TEM/EDX elemental mapping of the CeO 2 /LDPE particles. Although there is a C element on the gold grid, the profile of the CeO 2 /LDPE particles is still clearly shown by the C elemental map.…”

“…Therefore, the UHMWPE composite membranes have a potential application as garments for low-intensity X-ray shielding applications. 13,14 A PM4L planetary ball mill (Droide Co., Ltd., China) with Zirconia balls of 5 mm diameter and two stainless steel vials was used for ball milling. The weight ratio of the ballto-CeO 2 powders was 10:1, the weight ratio between raw CeO 2 and polymeric surfactant (LDPE) powders was 5:1, and cyclohexane was used as a process control agent, which was mixed with CeO 2 and LDPE powders with a volume-to-mass ratio of 0.6:1.…”

Enhancement of mechanical properties of ultra‐high molecular weight polyethylene nanocomposites without losing thermal stability

“…The structure and properties of the materials are susceptible to the processing methods; therefore, a large number of references [3][4][5]9,12,[18][19][20][21][22][23][24][28][29][30] were used to adopt a procedure similar to commonly published approaches. A hydraulic hot press was used to make specimens with dimensions of 10 mm  10 mm  1 mm.…”

“…As previously said, UHMWPE requires specific processing conditions under relatively high temperatures, which may lead to thermal degradation of the macromolecular chains when combined with other materials. On this point, it is worth noting that, in most investigations, many authors [3][4][5]9,[18][19][20][21][22][23][24] performed a thermal analysis of composite polymers but reached conclusions on thermal performance without considering a series of relevant details concerning the production route and the measurement and characterization methods. Some works in the literature have already shown changes in the thermal stability of the UHMWPE matrix by adding Al 2 O 3 microparticles and B 4 C nanoparticles individually.…”

Modification of polyethylene properties by encapsulation of inorganic material

“…The resulting particles volume distributions are shown in Figure 1 for the case involving the Al 2 O 3 additive. A light scattering technique as in [3] was used. We can observe that after 40 minutes of milling, the Al 2 O 3 peak disappears, which is an indication that encapsulation of Al 2 O 3 particles in the UHMWPE matrix is achieved.…”