Today's KNOWLEDGE Share: Polydicyclopentadiene (pDCPD):

Today's KNOWLEDGE Share

Polydicyclopentadiene (pDCPD):

Polydicyclopentadiene (pDCPD) is a relatively new polymer which is formed through Ring opening metathesis polymerisation (ROMP) of Dicyclopentadiene (DCPD).

pDCPD is a custom-engineered thermoset polymer designed to deliver an excellent combination of chemical, corrosion, and heat resistance, plus stiffness and impact strength. This material blends the molding flexibility of a thermoset with the high-performance characteristics of top engineering thermoplastics. It has a heat deflection temperature of up to 120°C.

pDCPD is unique because it has virtually no part size or weight limitations — parts with variable wall thicknesses, molded stiffening ribs, and more won’t slow down production. pDCPD is a relatively new material and its applications are limited as of yet, but it’s shown promise in corrosion-resistant chemical process equipment, septic tanks, and water treatment equipment.

Equipment

DCPD resins are transformed using high pressure RIM equipment as used in the polyurethane industry, with some small changes to be considered. As a reference, a widely used machine to inject DCPD resins is the Cannon A-100 fitted with a DCPD kit. The most important change is that the resin can never be in contact with air or moisture, which required a nitrogen blanket in the tanks. The tools or moulds are closed tools and are being clamped using a hydraulic press. Due to the fact that the resins shrink about 6% in volume during reaction, these presses (also called clamping units) don't have to handle high pressures such as for Sheet Moulding Compound (SMC) or expanding polyurethane.

Advantages of pDCPD:

Combines chemical, corrosion, and heat resistance

No part size or weight limitation – won’t slow down production

Blends molding flexibility with high performance

Disadvantages of pDCPD:

New material: applications are limited

Applications:

Since pDCPD is still a young material, the number of applications is quite limited. The major success story is in the field of body panels, mainly for tractors, construction equipment, trucks and buses. In the industrial applications, the main success story is components for chlor-alkali production (e.g. cell covers for electrolyzers). Other applications can be developed where impact resistance in combination with rigidity, 3D design and/or corrosion resistance is required.

source:terlene

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Today's KNOWLEDGE Share :Improving mechanical and flame retardant properties of Vinyl Ester Resin

Today's KNOWLEDGE Share

Improved mechanical and flame retardant properties of vinyl ester resin composites by combination of lithium-containing polyhedral oligomeric phenyl sesquisiloxanes and phosphorus-containing ionic liquid...

Vinyl ester resin (VER) are widely used in various applications, including automotive parts, yachts, wind turbine blades, and cooling towers, due to their excellent properties. However, the high flammability of VER limits its application in fields requiring stringent fire resistance. In this work, we used ionic liquid containing phospholipid structures (VIDHP) in combination with lithium-containing polyhedral oligomeric phenyl sesquisiloxanes (Li-POSS) to improve the mechanical and flame retardant properties of VER. The coordination between the VIDHP and Li-POSS increases the thermal stability of VIDHP and improve the solubility of Li-POSS in VER. The experimental results show an increase in initial decomposition temperature of VIDHP4/POSS1/VER compared to VIDHP/VER, while the solubility of Li-POSS in VER is improved. The Cone calorimeter results show that the total heat and smoke release of VIDHP4/POSS1/VER are reduced by 29.37 % and 36.55 % compared with the pure VER. The investigation of the flame retardant mechanism shows that the combined use of VIDHP and Li-POSS exhibits flame-retardant activity in both the gas and condensed phases, effectively enhancing the flame-retardant property of Vinyl Ester Resin.

source: https://www.sciencedirect.com

Authors:Zeqi Zhang, Liang Qiao, Xue Bi, Keshan Zhang ,Wenchao Zhang,Rongjie Yang

Better than PTFE and UHMWPE: New PA6 and UHMWPE Compound Optimizes Bridge Bearing Propertie

Plastics distributor Dreyplas and Spanish company Mekano4 (MK4), a specialist in technical solutions for bridge bearings and post-tensioning, have jointly developed MKSM® a thermoplastic sliding material. It combines excellent wear resistance with heat distortion temperature higher than 80ºC and a very low coefficient of friction. Mitsui Chemicals supplies the base polymers for this innovative alloy of PA6 with UHMWPE plus special additives, which has been patented for this application.

MK4’s structural bearings are in widespread use in construction and civil engineering, especially in bridges. MKSM transfers very high static loads in bridges, where its outstanding sliding behavior facilitates displacements and, in the case of curved sliding elements, also a limited degree of rotation in all axes between the bearing-mounted elements and the base structure. Compared to semi-finished product UHMWPE and PTFE, this new sliding material offers enhanced thermal properties, abrasion and heat distortion resistance. Its longer service life, compressive strength, and lower sliding friction can make it possible to use smaller sliding bearings. It can also replace fluoropolymers such as PTFE, which are currently the focus of controversy.

The base sheet with a thickness of 8 mm ± 0.2 mm is manufactured on a horizontal calender-extruder system by the fabricator SIMONA, in Kirn, Germany. MK4 produces the finished product by cutting the sliding bearing sheets to size and drilling recesses for oil lubrication.

As Dreyplas’ Marketing Director Norbert Hodrius explains, “Where particular requirements have previously meant that there were no alternatives to using fluoropolymers such as PTFE, PVDF etc., this high-performance compound, which is now part of our portfolio, offers advantageous solutions in many cases. Developing special UHMWPE-based compounds of this kind is just one of the services we offer our customers. Our many years of experience and close cooperation with Mitsui Chemicals mean we can use our development and materials expertise to bring products with real added value to market in a short time, as in this joint project with Mekano4.”

source:Dreyplas/konsens.de

Today's KNOWLEDGE Share:NREL Builds and Tests Wind Turbine Blade With Recyclable Resin:

Today's KNOWLEDGE Share

NREL Builds and Tests Wind Turbine Blade With Recyclable Resin:

Researchers at the Department of Energy’s National Renewable Energy Laboratory (NREL) published a paper in the journal Science describing the manufacture and testing of a composite wind turbine blade using a resin that is chemically recyclable and made from materials that can be bio-derived.

The new resin, nicknamed PECAN (polyester covalently adaptable network) performs on par with the current industry standard of blades made from a thermoset resin and outperforms certain thermoplastic resins intended to be recyclable.

Using incumbent technology, wind blades last about 20 years, and afterward they can be landfilled or shredded for use as concrete filler. The PECAN resin enables blades to be recycled using heat and methanol, producing materials that could be reused to manufacture new blades.

“It is truly a limitless approach if it’s done right,” says Ryan Clarke, postdoctoral researcher at NREL and first author of the paper. Clarke says the chemical recycling process was able to break down the 9-m prototype blade in about 6 hours.

“Nine meters is a scale that we were able to demonstrate all of the same manufacturing processes that would be used at the 60-, 80-, 100-meter blade scale,” says Robynne Murray, also an author on the paper.

Composites made from the PECAN resin held their shape, withstood accelerated weatherization validation and could be made within a time frame similar to the existing cure cycle for how wind turbine blades are currently manufactured.

The work was conducted by investigators at five NREL research hubs, including the National Wind Technology Center and the BOTTLE Consortium. The researchers demonstrated an end-of-life strategy for the PECAN blades and proposed recovery and reuse strategies for each component.

“The PECAN method for developing recyclable wind turbine blades is a critically important step in our efforts to foster a circular economy for energy materials,” says Johney Green, NREL’s associate laboratory director for Mechanical and Thermal Engineering Sciences.

source:NREL & www.ptonline.com

Today's KNOWLEDGE Share : Exposing the pitfalls of plastics mechanical recycling through cost calculation

Today's KNOWLEDGE Share

Exposing the pitfalls of plastics mechanical recycling through cost calculation:

The plastic industry needs to match the recycling goals set by the EU. Next to technological hurdles, the cost of plastics mechanical recycling is an important modality in this transition. This paper reveals how business economic cost calculation can expose significant pitfalls in the recycling process, by unravelling limitations and boundary conditions, such as scale.

By combining the business economic methodology with a Material Flow Analysis, this paper shows the influence of mass retention of products, the capacity of the processing lines, scaling of input capacity, and waste composition on the recycling process and associated costs. Two cases were investigated: (i) the Initial Sorting in a medium size Material Recovery Facility and (ii) an improved mechanical recycling process for flexibles − known as the Quality Recycling Process − consisting of Additional Sorting and Improved Recycling. Assessing the whole recycling chain gives a more holistic insight into the influences of choices and operating parameters on subsequent costs in other parts of the chain and results in a more accurate cost of recycled plastic products. This research concluded that the cost of Initial Sorting of flexibles is 110,08–122,53 EUR/t, while the cost of subsequent Additional Sorting and Improved Recycling ranges from 566,26 EUR/t for rPE Flex to 735,47 EUR/t for rPP Film, these insights can be used to determine a fair price for plastic products. For the Quality Recycling Process it was shown that rationalisation according to the identified pitfalls can reduce the cost per tonne of product by 15–26%.

source:Nicola Van Camp,Irdanto Saputra Lase , Steven De Meester,, Sophie Hoozée , Kim Ragaert 

Link:https://www.sciencedirect.com/science/article/pii/S0956053X24004513

Today's KNOWLEDGE Share:PACKING CHNAGES

Today's KNOWLEDGE Share

Why do thick parts need more packing than thin ones ?

Packing changes the parts size/volume/mass, but not the final density. Whatever is already solid at the end of fill (frozen skin) does not need any packing (shrinkage has already occurred !).

So, as the picture shows (in a slightly exaggerated way) in a thin part/section one only has to pack a tiny fraction of the total volume, whereas in a thick part/section, most of the volume will need to be packed, to compensate for the shrinkage.

Since thick parts are easy to fill and need more packing, it is not unusual to use a packing pressure much higher than the filling pressure. Something that might not fit the default values proposed by simulation...

Always think twice before accepting a default value.

source:Vito Leo