Search

Highlights In high‐power lighting, large‐screen display, and other practical application scenarios, Light diffusing materials (LDMs) with favorable thermal conductivity are desired to assist in heat dissipation. In this paper, platy magnesium hydroxide (pMH) and mesoporous spherical magnesium hydroxide (sMH) were introduced as scattering particles for the first time to prepare polystyrene (PS)‐based LDMs. The limited refractive index mismatch allowed MH to be filled in large quantities with less sacrifice of light transmission performance. Owing to the complex surface morphology and large specific surface area, sMH possesses stronger scattering capability, and its combination addition with pMH could effectively increase scattering range. Meanwhile, an effective filler network was constructed with the combined use of pMH and sMH, and thus enhanced the thermal conductivity of the composites. Additionally, PS/pMH‐sMH composites exhibited higher thermal stability. This study expands the auxiliary thermal management capability of light diffusion materials and presents a new application possibility for MH as scattering particles. A new application possibility for Magnesium hydroxide as scattering particles. Light transmittance degradation of PS/MH at high filler loadings was mitigated by RI matching. Complex surface morphology endowed sMH with strong scattering capability. Optimal filling ratio of pMH to sMH was tested for better scattering performance. Extended scattering range, improved TC and thermal stability was achieved. [ABSTRACT FROM AUTHOR]

The expansion of deformation-induced crystallization of polypropylene (PP) pipes was studied. The crystal structure and melting characteristics of the samples after expanding at different expansion strains and expansion temperatures were analyzed. The results showed that the ciystallinity was improved when the PP pipes were expanded, and the expansion effect made the crystal structure more perfect while the expanding temperature did not exceed the crystallization temperature. However, once expanding temperature exceeded crystallization temperature, some [beta] lamellae crystal were stretched and transformed into a crystals structure. It showed that the expansion effect could cause the crystal phase transformation of the sample. In addition, when the expanding strain was less than 15%, the [beta] crystal diffraction peak intensity of the sample decreased, but the a crystal diffraction peak intensity increased, and the original sparse distribution lamellae structure gradually became compact. With the expanding strain continued to increase, the oriented molecular chains underwent stress relaxation, which hindered the conversion of [beta] crystals to a crystals. The oriented crystal structure formed by the crystal phase transformation made the PP pipe have excellent tensile and impact strength. As a result, the hoop tensile strength is increased by 13%, and the impact strengths are increased by 36%. KEYWORDS expanding, phase transformation, PP pipe, [beta] crystals, 1 | INTRODUCTION As we all know, polypropylene is widely used in packaging, home appliances, and automobiles due to its good mechanical properties and easy processing and molding. [1-4] As [...]

In this study, we presented a one‐step melt‐blending method to fabricate polypropylene (PP)/polycarbonate (PC) light‐diffusing materials. A promising balance between haze and transmittance was obtained by the addition of small amount of PC to the matrix. On the basis of Mie scattering theory and morphology analysis, the correlation between processing conditions and light‐diffusing properties was built. Low rotor speed and high viscosity ratio were beneficial to optical properties of PP/PC composites. To extend the advanced application, two general anti‐ultraviolet additives nanoscale titanium dioxide (Nano‐TiO2) and 2‐(2‐hydroxy‐5‐methylphenyl) benzotriazole (UV‐P) were added to impart UV‐shielding property to the composites. Their specific influences on the morphology and comprehensive properties of PP/PC composites were studied. It was found that the introduction of Rayleigh scattering raised by Nano‐TiO2 could strengthen the scattering effect and cause a significant reduction in light transmittance, while UV‐P had little effect on the optical properties of the light‐diffusing composites. In summary, this study prepared the PP/PC composites with high‐performance light scattering and UV‐shielding properties applying a facile blending method, which showed a potential application in flexible lightings and LCD displays. [ABSTRACT FROM AUTHOR]

Based on the FLUENT software, the VOF model was adopted to study the changes of the melt delamination in the flow channel when the four-layer melt was multiplied to the eight-layer one by a laminator under different wall slip degrees and flow channel structure parameters. The analysis results indicated that the reduction of the degree of wall slip led to the accumulation of the melt on the upper and lower wall surfaces. This led to an increase in thickness of the melt layer at the upper and lower wall surfaces. The three structural parameters of fillet radius between the confluence section and the exit section, expansion angle of the confluence section and length of the equilibrium section only affected the accumulation of the melt on the left and right wall surfaces and therefore inflenced the dimensional accuracy of the melt in each layer. The influence of the angle was most signficant, followed by the length of equilibrium section. However, the influence was least from the radius of the fillet. [ABSTRACT FROM AUTHOR]