Abstract: With the increasing deterioration of the global environment, many enterprises are becoming aware of the importance of protecting the environment, and maximizing the use of resources is one of the initiatives of some manufacturing enterprises. For example, Taylor Guitars used to use only the most top-quality raw materials to produce their products, and the remaining raw materials were discarded, which resulted in a huge waste. But now Taylor Guitar uses the remaining raw materials wasted before to produce low-end co-products, and sells them through e-commerce platforms. We establish a secondary supply chain consisting of an original manufacturer, a co-product manufacturer, and an e-commerce platform. Considering the better environmental protection characteristics of co-products, e-commerce platforms choose to promote co-products to increase consumers' favorability towards them. In this paper, we consider the two most common forms of promotion: subsidies and marketing efforts. Firstly, this paper establishes a Stackelberg game model to study the optimal marketing decisions of the manufacturer and the platform for co-products under no promotion of by-products by the platform (Model B), subsidy promotion (Model S) and marketing effort promotion (Model E), respectively.
It is found that the price of co-products is not only influenced by the minimum quality of raw materials for co-products, but also closely related to the level of consumers' environmental awareness. In Model B and Model E, when consumers' environmental awareness is at a low level, the better the quality of the remaining raw materials, the higher the price of co-products; but when consumers' environmental awareness is high, the minimum quality of the remaining raw materials will not lead to a sustained increase in the price of co-products, but rather a downward trend followed by a rebound. This indicates that enterprises should fully consider various factors such as consumers' demands and expectations when making green marketing decisions, and make different production and marketing decisions according to the differences of consumer groups.
Next, we compare the optimal prices of the two products under the three models. This is a very important issue because it will directly affect the marketing decisions and product promotion decisions of the manufacturer and e-commerce platform. The quality of co-products and the commission rate of the e-commerce platform simultaneously affect the price of co-products. The results show that when the quality of the co-product is low, the price of the co-product will be the highest under the subsidy promotion and the lowest under the marketing effort promotion if the commission rate is low. If the commission rate is at a moderate level, the price of the co-product is still the highest under subsidy promotion and the lowest under no promotion. If the commission rate is high, the price of the co-product is the highest under marketing effort promotion and the lowest under no promotion. In the case of high co-product quality, if the commission rate is low, the price of a co-product will be the highest when subsidy promotion is carried out and the lowest when marketing effort promotion is carried out. If the commission rate is at a medium-high level, the co-product's price will be the highest under subsidy promotion, but the price will be the lowest under no promotion.
Finally, the optimal promotion decision of the co-product is made according to the demand of the two products. Between Model B and Model S, it will be more efficient for the platform to adopt subsidy promotion when the quality of the co-product is low. When the quality of the co-product is high, more consumers can be attracted to choose the co-products without promotion. When the quality of co-products is at a medium level, the level of consumers' environmental awareness should also be taken into account. The choice between no promotion and marketing effort to promote depends on the quality of the remaining raw materials and the environmental awareness of consumers. When the quality of the remaining raw materials is low, the platform will not need to promote them, and the green degree of co-products will have an obvious advantage. When the quality of the remaining raw materials is high, it will be wise for the platform to adopt marketing effort. When the quality of the remaining raw materials is at a medium level, the choice of promotion strategy will depend on the environmental awareness of the consumers. If the environmental awareness of the consumers is low, there will be no need for promotion. If the consumers pay more attention to environmental protection, then the marketing effort will play a significant role.

Key words: e-commerce platform, co-product, product competition, platform subsidy, marketing effort

摘要： 在由原始制造商、副产品制造商和电商平台构成的供应链中,考虑消费者环保意识在系统中的作用,本文研究了制造商对副产品的经营决策以及平台对推广模式的抉择。在平台对副产品分别实施不推广(模型B)、补贴推广(模型S)和营销努力推广(模型E)模式下,建立Stackelberg博弈模型,求得最优的定价决策。研究发现:副产品的价格同时受到副产品原材料最低质量和消费者环保意识的影响,在营销努力推广下,消费者的环保意识较低时,副产品的价格随着它原材料质量的升高而升高;环保意识较高时,则取决于使用剩余原材料质量水平的高低。补贴推广并不总能起到促进副产品销售的作用,只有在副产品质量较低或质量适中且消费者环保意识较低时,平台才应该实施补贴推广。当副产品的原材料质量水平较低或中等且消费者环保水平较低时,营销努力反而对副产品市场的扩散起负作用。

关键词: 电商平台, 副产品, 产品竞争, 平台补贴, 营销努力