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Polymer-particle composites, which have demonstrated wide applications ranging from energy harvesting and storage, biomedical applications, electronics and environmental sensing to aerospace applications, have been investigated for decades. However, fabricating polymer-particle composites with controlled distribution of particles in polymer continues to be a fundamental challenge. As to date, a few additive manufacturing (AM) technologies can fabricate composites, however, with a limited choice of materials or limited dispersion control. Against this background, this research investigated a hybrid polymer-particle composite manufacturing process, projection electro-stereolithography (PES) process, which integrates electrostatic deposition and projection based stereolithography (SL) technologies.

In PES process, a photoconductive film collects charged particles in the regions illuminated by light. Then, collected particles are transferred from the film to a polymer layer with defined patterns. Lastly, a digital mask is used to pattern the light irradiation of the digital micromirror device chip, selectively curing the photopolymer liquid resin and particles of that layer. By transferring particles from the photoconductive film to the photopolymer in a projection-based SL system, multi-material composites with locally controlled dispersions could be produced. A proof-of-concept PES testbed was developed. Various test cases have been performed to verify the feasibility and effectiveness of the developed approach.

Challenges in this novel AM process, including process design, particle patterning and transferring, are addressed in this paper. It is found that particles can be transferred to a layer of partially cured resin completely and accurately, by using the stamping approach. The transferring rate is related to stamping force and degree of conversion of the recipient layer. The developed hybrid process can fabricate polymer-particle composites with arbitrary dispersion pattern, unlimited printable height and complicated geometries.

Although an electrostatic deposition process has been investigated as a 3D printing technology for many years, it is the first attempt to integrate it with projection SL for fabricating multi-material polymer composite components. The novel hybrid process offers unique benefits including local dispersion control, arbitrary filling patterns, wide range of materials, unlimited printable height and arbitrary complicated geometries.

This paper aims to exploit shape memory polymer (SMP) composite as multifunctional coatings for protecting substrates from surface wear and bacterial. The efficiency of added nano or micro-sized particles in enhancing the properties of SMP was investigated. This study also attempts to use a low-cost and effective spraying approach to fabricate the coatings. The coatings are expected to have good conformability with the substrate and deliver multi-functional performance, such as wrinkle free, wear resistance, thermal stability and antimicrobial property.

High-performance SMP composite coatings or thin films were fabricated by a home-made continuous spray-deposition system. The morphologies of the coatings were studied using the scanning electron microscope and the transmission electron microscope. The abrasion properties were evaluated by Taber Abraser test, and thermo-gravimetric analysis was carried out to investigate the thermal properties of prepared composites. The antimicrobial property was determined by the inhibition zone method using E. coli. The thermally responsive shape memory effect of the resulting composites was also characterized.

The morphology analysis indicated that the nanoclay was distributed on the surface of the coating which resulted in a significant improvement of the wear property. The wear resistance of the coatings with nanoclay was improved as much as 40 per cent compared with that of the control sample. The thermo-gravimetric analysis revealed that the weight loss rate of composites with nanoclay was dropped over 40 per cent. The SMP coating with zinc oxide (ZnO) showed excellent antimicrobial effect. The shape recovery effect of SMP/nanoclay and SMP/ZnO composites can be triggered by external heating and the composites can reach a full shape recovery within 60 s.

This study proposed a continuous spray-deposition fabrication of SMP composite coatings, which provides a new avenue to prepare novel multi-functional coatings with low cost.

Most studies have emphasized on the sole property of SMP composites. Herein, a novel SMP composite coating which could deliver multi-functionality such as wrinkle free, wear resistance, thermal stability and antimicrobial property was proposed.

Printing toners are polymer composites accountable for transmission of digital images onto target substrates. Bearing in mind the ever increasing demand for high quality digital printing, modification and/or integration of existing techniques for manufacturing toners with favourable morphological and colour characteristics appears of vital importance. The present study aims to uncover the significance of in-situ polymerisation method, i.e. suspension, emulsion and mini-emulsion to control the microstructure of toner particles (particle size, particle size distribution and sphereness) while keeping the energy required for polymerisation along with reaction conversion at a reasonable level.

Assessment of particle size, particle size distribution and reaction conversion visualised the potential of suspension, emulsion and mini-emulsion polymerisation techniques to control microstructure, and colour characteristics of synthesized toners as well.

The results provided support for the fact that either the emulsion or mini-emulsion polymerisation routes will result in toners having an acceptable particle size and particle size distribution in the presence of a redox precursor. The higher monomer conversion at low temperature, as compared to the suspension polymerisation, was noticeable.

Analysing the glass transition temperature and colour characteristics of the resulting toners elucidated the superiority of mini-emulsion with respect to the other two cases which ranks this method on account of application.

For the first time, mini-emulsion route was put into practice and toners with acceptable colour and microstructure features were synthesised. In spite of lower polymerisation temperature and higher conversion of mini-emulsion compared to suspension and emulsion polymerisation techniques, further investigations are required to fine-tuning the properties of toners produced through this method.

This contribution aims to introduce an effective low cost polymer-nanocomposite for possible application to achieve a super protection for highly damaged ancient Egyptian wall paintings.

SiO2 and Al2O3 nanoparticles were synthesized by the sol-gel method. Then, the polymer-nanocomposite was prepared by simple mixing and dispersing the nanoparticles into the tetraethoxysilane polymer solution, with the aid of an ultrasonic dismembrator. The application of the polymer-nanocomposite and other polymeric nanodispersions, on laboratory models, was performed by the brushing technique. Next, the materials stability was evaluated by means of digital optical microscope, colorimetry, FE-scanning electron microscope, measuring the static contact angle and water absorption rates.

The results were promising in creating a superhydrophobicity and the static contact angle (?S) measured for the polymer-nanocomposite reached 135o. An average of three measurements of the water absorption rate after polymer-nanocomposite treatment was 0.66 g/m2 s, compared to 2.60 g/m2 s for the control model (untreated). Further, an average of color difference (?E*) for the treated surface was 2.78, and after the accelerated thermal aging was 3.6. Observing the surface morphology, the polymer-nanocomposite enhanced the roughness of the treated surface and showed a high resistance to laboratory salt weathering.

Preparation of a polymer-nanocomposite by adding SiO2 and Al2O3 NPs to tetraethoxysilane polymer has been proposed. As a promising conservation material, the produced polymer-nanocomposite helped to form an efficient protective film.

This paper attains to develop an economic polymer-nanocomposite to maintain a high protection to damaged ancient Egyptian wall paintings and similar objects.

This paper aims to study the effects of solid additives and compounding processes on the selective laser sintering (SLS) behavior of composite powders.

Composite powders were prepared from TrueForm™ acrylic‐styrene co‐polymer and SiO₂ powder. Dry mixing and melt extrusion were used as the blending processes to produce the composite powders. Some SiO₂ powder was ground and treated with silane coupling agent before blending to study the effects of particle size and surface treatment of the filler, respectively. The temperature of the powder bed was monitored using an infrared thermometer. The fusion behaviors of the powders were investigated in situ using an optical microscope and the sintered specimens were examined by scanning electron microscopy.

For a given volume fraction of the filler, reducing its particle size will hinder fusion between the polymer particles and weaken the sintered specimens. Surface treatment of the filler by silane coupling agent had little effect on the morphology of the sintered specimens; however, it slightly improved their strength. The blending method plays an important role in the sintering behavior of the composite powders. Although melt blending improved the polymer‐to‐polymer contact between the composite powder particles, the high‐resultant viscosity of the material adversely affected the densification of the powder bed, leading to a highly porous structure of the sintered specimens.

The sintering experiments were conducted in ambient conditions using a laser engraving machine instead of a commercial SLS machine with atmospheric control. The temperature gradient within the powder bed was expected to be higher than that in normal SLS processes.

The SLS behavior of a composite powder not only depends on its composition but also on the powder preparation method or powder morphology.

This paper provides some useful information for future development of composite powders for SLS applications.

The purpose of this paper is to demonstrate the processability of cohesive PE-HD particles in laser beam melting processes (LBM) of polymers. Furthermore, we present a characterization method for polymer particles, which can predict the quality of the powder deposition via LBM processes.

This study focuses on the application of dry particle coating processes to increase flowability and bulk density of PE-HD particles. Both has been measured and afterwards validated via powder deposition of PE-HD particles in a LBM machine.

For efficient coating in a dry particle coating process, the PE-HD particles and the attached nanoparticles need to show similar surface chemistry, i.e. both need to behave either hydrophobic or hydrophilic. It is demonstrated that dry particle coating is appropriate to enhance flowability and bulk density of PE-HD particles and hence considerably improves LBM processes and the resulting product quality.

At present, in LBM processes mainly polyamide (PA), 12 particles are used, which are so far quite expensive in comparison to, for example, PE-HD particles. This work provides a unique and versatile method for nanoparticulate surface modification which may be applied to a wide variety of materials. After the coating, the particles are applicable for the LBM process. Our results provide a correlation between flowability and bulk density and the resulting product quality.

Toner is a crucial dry colorant composite used in printing based on the electrophotographic process. The quality of printed images is greatly influenced by the toner production method and material formulation. Chemically in situ polymerization methods are currently preferred. This paper aims to optimize the characteristics of a composite produced through emulsion polymerization using common raw materials for electrophotographic toner production.

Emulsion polymerization provides the possibility to optimize the physical and color properties of the final products. Response surface methodology (RSM) was used to optimize variables affecting particle size (PS), PS distribution (PSD), glass transition temperature (T_g°C), color properties (ΔE) and monomer conversion. Box–Behnken experimental design with three levels of styrene and butyl acrylate monomer ratios, carbon black pigment and sodium dodecyl sulfate surfactant was used for RSM optimization. Additionally, thermogravimetric analysis and surface morphology of composite particles were examined.

The results indicated that colorants with small PS, narrow PSDs, spherical shape morphology, acceptable thermal and color properties and a high percentage of conversion could be easily prepared by optimization of material parameters in this method. The anticipated outcome of the present inquiry holds promise as a guiding beacon toward the realization of electrographic toner of superior quality and exceptional efficacy, a vital factor for streamlined mass production.

To the best of the authors’ knowledge, for the first time, material parameters were evaluated to determine their impact on the characteristics of emulsion polymerized toner composites.

This paper presents the results from the evaluation of different types of flexible substrates for high‐density flip chip application. In this work two different types of base materials were used, epoxiglass (EG) and polyimide (PI). According to previous tests the type of conductive particles in the adhesive seems to be one of the key factors in high‐density interconnections. The adhesive selected for these tests was a composite of epoxy matrix and high content of isolated soft metal‐coated polymer particles. Two different test structures with contact areas of 50 × 50μm and 50 × 90μm were compared. The total amount of contacts in one IC was approximately 200 and the effective pitch size was 80μm. The contact resistances were measured by four‐point method and the continuity by daisy chain structure. The reliability of the flip chip interconnections was tested in thermal cycling and humidity tests.

The purpose of this paper is to study the effect of monomer composition in core‐shell latex prepared from co‐polymer of styrene‐butylacrylate (BA)‐methyl methacrylate (MMA) and their paint properties.

The core‐shell latex was prepared by a stepwise semi‐batch emulsion polymerisation. A set of dispersion was made with the different core‐shell compositions. The core phase consists of a copolymer of styrene‐BA‐acrylic acid (AA) and the shell phase consists of a copolymer of MMA‐AA. The properties of latex were determined by solid content, viscosity, pH and particle size. Subsequently, emulsion paint (PVC‐37 per cent and NVM‐53 per cent) was prepared using core‐shell latex. The paint properties were determined by block resistance, gloss, elongation at break, etc. The particle morphology was characterised with transmission electron microscope (TEM).

Core‐shell structure of latex was confirmed by TEM. The performance of core‐shell latex has been optimised and the best combination achieved with 25‐40 per cent of hard phase in core‐shell latex.

Although the core‐shell structured latex was prepared from co‐polymer of styrene‐BA‐MMA monomer, the system could be extended with other monomers depending on the end use of surface coating.

The paint industry may use this method to improve paint properties.

The paper shows that, by use of core‐shell latex, it is possible to achieve high‐block resistance, hardness, elasticity and gloss.

The purpose of this paper is to investigate the effect of different heating approaches during thermal rounding of polymer powders on powder bulk properties such as particle size, shape and flowability, as well as on the yield of process.

This study focuses on the rounding of commercial high-density polyethylene polymer particles in two different downer reactor designs using heated walls (indirect heating) and preheated carrier gas (direct heating). Powder bulk properties of the product obtained from both designs are characterized and compared.

Particle rounding with direct heating leads to a considerable increase in process yield and a reduction in powder agglomeration compared to the design with indirect heating. This subsequently leads to higher powder flowability. In terms of shape, indirect heating yields not only particles with higher sphericity but also entails substantial agglomeration of the rounded particles.

Shape modification via thermal rounding is the decisive step for the success of a top-down process chain for selective laser sintering powders with excellent flowability, starting with polymer particles from comminution. This report provides new information on the influence of the heating mode (direct/indirect) on the performance of the rounding process and particle properties.